{"id":935,"date":"2026-07-10T19:52:27","date_gmt":"2026-07-10T19:52:27","guid":{"rendered":"https:\/\/pccaselab.com\/test\/?page_id=935"},"modified":"2026-07-21T00:49:14","modified_gmt":"2026-07-21T00:49:14","slug":"free-raid-capacity-calculator","status":"publish","type":"page","link":"https:\/\/pccaselab.com\/test\/free-raid-capacity-calculator","title":{"rendered":"Free RAID Capacity Calculator"},"content":{"rendered":"\n<style>\n.pcl-raid-hero{--ink:#15141b;--ink-soft:#5b5866;--bg:#f8f9fb;--surface:#fff;--surface-2:#eef0f4;--border:#e2e5ec;--accent:#6d4fd6;--accent-ink:#5a3fc0;--radius:16px;--sans:'Manrope',-apple-system,'Segoe UI',sans-serif;--mono:'IBM Plex Mono',ui-monospace,monospace;font-family:var(--sans);color:var(--ink);}\n.pcl-raid-hero *{box-sizing:border-box;}\n.pcl-raid-hero a{color:inherit;text-decoration:none;}\n\n.pcl-raid-hero .pcl-hero{width:100vw;margin-left:calc(50% - 50vw);margin-right:calc(50% - 50vw);padding:60px 0 56px;position:relative;overflow:hidden;border-bottom:1px solid var(--border);background:var(--bg);}\n.pcl-raid-hero .pcl-blob{position:absolute;width:400px;height:400px;border-radius:50%;background:radial-gradient(circle,var(--accent) 0%,transparent 70%);opacity:.14;top:-160px;right:-100px;filter:blur(10px);pointer-events:none;}\n.pcl-raid-hero .pcl-hero-inner{max-width:1180px;margin:0 auto;padding-left:28px;padding-right:28px;display:flex;gap:48px;align-items:center;flex-wrap:wrap;position:relative;}\n.pcl-raid-hero .pcl-hero-copy{flex:1 1 460px;min-width:300px;}\n.pcl-raid-hero .pcl-crumb{display:flex;align-items:center;gap:10px;font-size:.85rem;color:var(--ink-soft);margin:0 0 18px;flex-wrap:wrap;}\n.pcl-raid-hero .pcl-crumb a{color:var(--ink-soft);}\n.pcl-raid-hero .pcl-crumb a:hover{color:var(--accent-ink);}\n.pcl-raid-hero .pcl-hero-eyebrow{font-family:var(--mono);text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:600;color:var(--accent-ink);margin:0 0 16px;}\n.pcl-raid-hero .pcl-hero-title{font-size:clamp(2rem,4vw,2.8rem);line-height:1.1;letter-spacing:-.02em;margin:0 0 20px;font-weight:800;color:var(--ink);}\n.pcl-raid-hero .pcl-hero-sub{font-size:1.04rem;color:var(--ink-soft);max-width:56ch;margin:0;}\n.pcl-raid-hero .pcl-hero-media{flex:1 1 420px;min-width:300px;max-width:560px;}\n.pcl-raid-hero .pcl-hero-frame{aspect-ratio:4\/3;border-radius:var(--radius);border:1px solid var(--border);background:linear-gradient(135deg,var(--surface-2),var(--surface));position:relative;overflow:hidden;box-shadow:0 30px 60px -30px rgba(21,20,27,.25);}\n.pcl-raid-hero .pcl-hero-frame-placeholder{position:absolute;top:20%;left:0;right:0;text-align:center;font-family:var(--mono);font-size:11px;letter-spacing:.08em;color:var(--ink-soft);text-transform:uppercase;}\n.pcl-raid-hero .pcl-hero-frame-img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;margin:0;}\n<\/style>\n\n<div class=\"pcl-raid-hero\">\n<section class=\"pcl-hero\">\n  <span class=\"pcl-blob\" aria-hidden=\"true\"><\/span>\n  <div class=\"pcl-hero-inner\">\n    <div class=\"pcl-hero-copy\">\n      <p class=\"pcl-crumb\"><a href=\"\/\">Home<\/a><span>\/<\/span><span>Free RAID Capacity Calculator<\/span><\/p>\n      <p class=\"pcl-hero-eyebrow\">Free Tool &middot; Instant Results &middot; All RAID Levels<\/p>\n      <h1 class=\"pcl-hero-title\">Free RAID Capacity Calculator<\/h1>\n      <p class=\"pcl-hero-sub\">Trying to plan a NAS, server, or data center build without understanding how many usable spaces will be available to you is a very expensive error. Enter the quantity of disks you have, the capacity of those disks individually, and the RAID level, and this calculator will give you your exact usable capacity in less time than it takes to complete a rebuild.<\/p>\n    <\/div>\n    <div class=\"pcl-hero-media\">\n      <div class=\"pcl-hero-frame\">\n        <span class=\"pcl-hero-frame-placeholder\">Photo &mdash; NAS drive bay array<\/span>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/section>\n<\/div>\n\n\n\n\n<style>\n.pcl-raid-tool{--ink:#15141b;--ink-soft:#5b5866;--bg:#f8f9fb;--surface:#fff;--border:#e2e5ec;--radius:16px;--sans:'Manrope',-apple-system,'Segoe UI',sans-serif;font-family:var(--sans);}\n.pcl-raid-tool *{box-sizing:border-box;}\n\n.pcl-raid-tool .pcl-section--calc{width:100vw;margin-left:calc(50% - 50vw);margin-right:calc(50% - 50vw);padding:56px 28px;background:var(--bg);}\n.pcl-raid-tool .pcl-calc-embed{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;width:100%;}\n.pcl-raid-tool .pcl-calc-disclaimer{font-size:.82rem;color:var(--ink-soft);margin:16px auto 0;max-width:640px;text-align:center;}\n<\/style>\n\n<div class=\"pcl-raid-tool\">\n<section class=\"pcl-section--calc\">\n  <div class=\"pcl-calc-embed\"><script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"RAID Capacity Calculator\",\"url\":\"https:\/\/pccaselab.com\/raid-calculator\",\"applicationCategory\":\"UtilityApplication\",\"operatingSystem\":\"Web Browser\",\"description\":\"Free RAID capacity calculator for NAS and server builds. Calculate usable storage for RAID 0, 1, 5, 6, 10, Synology SHR, UnRAID and ZFS RAIDZ. Includes rebuild time estimates and smart warnings.\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"USD\"},\"author\":{\"@type\":\"Organization\",\"name\":\"PCCaseLab\",\"url\":\"https:\/\/pccaselab.com\"}}\n<\/script>\n\n<div id=\"r4\" class=\"r4\">\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 HERO \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-hero\">\n    <div class=\"r4-hero-left\">\n      <p class=\"r4-eyebrow\">Free tool \u00b7 PCCaseLab<\/p>\n            <h2 class=\"r4-h1\">RAID Capacity<br>Calculator<\/h2>\n      <p class=\"r4-lead\">Calculate usable storage, rebuild times and drive costs for any RAID level \u2014 including Synology SHR, UnRAID and ZFS.<\/p>\n    <\/div>\n    <div class=\"r4-hero-result\">\n      <p class=\"r4-result-label\">Usable storage<\/p>\n      <div class=\"r4-result-num\" id=\"r4-hero-num\" aria-live=\"polite\">\u2014<\/div>\n      <p class=\"r4-result-sub\" id=\"r4-hero-sub\">Select your drives below<\/p>\n      <div class=\"r4-result-pills\" id=\"r4-result-pills\"><\/div>\n    <\/div>\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 PLATFORM TABS \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-tabs-wrap\">\n    <div class=\"r4-tabs\" role=\"tablist\">\n      <button class=\"r4-tab active\" data-p=\"standard\" onclick=\"r4Platform(this)\" role=\"tab\">Standard RAID<\/button>\n      <button class=\"r4-tab\" data-p=\"synology\"        onclick=\"r4Platform(this)\" role=\"tab\">Synology SHR<\/button>\n      <button class=\"r4-tab\" data-p=\"unraid\"          onclick=\"r4Platform(this)\" role=\"tab\">UnRAID<\/button>\n      <button class=\"r4-tab\" data-p=\"zfs\"             onclick=\"r4Platform(this)\" role=\"tab\">ZFS \/ TrueNAS<\/button>\n    <\/div>\n    <p class=\"r4-tab-desc\" id=\"r4-tab-desc\">Standard hardware or software RAID. All drives should be the same size.<\/p>\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 CONTROLS ROW \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-controls\">\n\n    <div class=\"r4-ctrl\">\n      <label class=\"r4-label\" for=\"r4-drive\">Drive model<\/label>\n      <select id=\"r4-drive\" class=\"r4-select\" onchange=\"r4Calc()\">\n        <optgroup label=\"Seagate IronWolf \u2014 CMR NAS HDD\">\n                    <option value=\"0\" data-tb=\"4\" data-price=\"79\" data-asin=\"B07H289S7C\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf 4TB \u2014 $79<\/option>\n                    <option value=\"1\" data-tb=\"6\" data-price=\"99\" data-asin=\"B01LOOJBQY\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf 6TB \u2014 $99<\/option>\n                    <option value=\"2\" data-tb=\"8\" data-price=\"129\" data-asin=\"B01LOOJBQU\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf 8TB \u2014 $129<\/option>\n                    <option value=\"3\" data-tb=\"12\" data-price=\"199\" data-asin=\"B07H291F6C\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf 12TB \u2014 $199<\/option>\n                    <option value=\"4\" data-tb=\"16\" data-price=\"289\" data-asin=\"B07H3WLLYD\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf 16TB \u2014 $289<\/option>\n                    <option value=\"5\" data-tb=\"20\" data-price=\"399\" data-asin=\"B09YWHDMFJ\" data-type=\"hdd\" data-smr=\"0\">Seagate IronWolf Pro 20TB \u2014 $399<\/option>\n                  <\/optgroup>\n        <optgroup label=\"WD Red \u2014 CMR NAS HDD\">\n                    <option value=\"6\" data-tb=\"4\" data-price=\"74\" data-asin=\"B08TZPS4QQ\" data-type=\"hdd\" data-smr=\"0\">WD Red Plus 4TB \u2014 $74<\/option>\n                    <option value=\"7\" data-tb=\"6\" data-price=\"94\" data-asin=\"B08V18M4KK\" data-type=\"hdd\" data-smr=\"0\">WD Red Plus 6TB \u2014 $94<\/option>\n                    <option value=\"8\" data-tb=\"8\" data-price=\"129\" data-asin=\"B08V174F8P\" data-type=\"hdd\" data-smr=\"0\">WD Red Plus 8TB \u2014 $129<\/option>\n                    <option value=\"9\" data-tb=\"12\" data-price=\"219\" data-asin=\"B07YFGQN5L\" data-type=\"hdd\" data-smr=\"0\">WD Red Pro 12TB \u2014 $219<\/option>\n                    <option value=\"10\" data-tb=\"16\" data-price=\"299\" data-asin=\"B08M9TPDMJ\" data-type=\"hdd\" data-smr=\"0\">WD Red Pro 16TB \u2014 $299<\/option>\n                    <option value=\"11\" data-tb=\"2\" data-price=\"49\" data-asin=\"B084ZTSPV4\" data-type=\"hdd\" data-smr=\"1\">WD Red SMR 2TB \u26a0 \u2014 $49<\/option>\n                  <\/optgroup>\n        <optgroup label=\"Toshiba N300 \u2014 CMR NAS HDD\">\n                    <option value=\"12\" data-tb=\"4\" data-price=\"69\" data-asin=\"B01LXUH3DM\" data-type=\"hdd\" data-smr=\"0\">Toshiba N300 4TB \u2014 $69<\/option>\n                    <option value=\"13\" data-tb=\"8\" data-price=\"119\" data-asin=\"B01LXUH3EV\" data-type=\"hdd\" data-smr=\"0\">Toshiba N300 8TB \u2014 $119<\/option>\n                  <\/optgroup>\n        <optgroup label=\"NAS SSDs\">\n                    <option value=\"14\" data-tb=\"1\" data-price=\"79\" data-asin=\"B08PC5YWZM\" data-type=\"ssd\" data-smr=\"0\">Samsung 870 EVO 1TB SSD \u2014 $79<\/option>\n                    <option value=\"15\" data-tb=\"2\" data-price=\"139\" data-asin=\"B08PC83269\" data-type=\"ssd\" data-smr=\"0\">Samsung 870 EVO 2TB SSD \u2014 $139<\/option>\n                    <option value=\"16\" data-tb=\"4\" data-price=\"269\" data-asin=\"B08QBJ2YM9\" data-type=\"ssd\" data-smr=\"0\">Samsung 870 EVO 4TB SSD \u2014 $269<\/option>\n                    <option value=\"17\" data-tb=\"1\" data-price=\"89\" data-asin=\"B08565SQLS\" data-type=\"ssd\" data-smr=\"0\">WD Red SA500 1TB SSD \u2014 $89<\/option>\n                    <option value=\"18\" data-tb=\"2\" data-price=\"149\" data-asin=\"B08564N1Y3\" data-type=\"ssd\" data-smr=\"0\">WD Red SA500 2TB SSD \u2014 $149<\/option>\n                    <option value=\"19\" data-tb=\"1.92\" data-price=\"199\" data-asin=\"B07KP7KTNR\" data-type=\"ssd\" data-smr=\"0\">Seagate IronWolf 110 1.92TB SSD \u2014 $199<\/option>\n                  <\/optgroup>\n        <option value=\"custom\" data-tb=\"0\" data-price=\"0\" data-asin=\"\" data-type=\"hdd\" data-smr=\"0\">\u2014 Enter custom size below \u2014<\/option>\n      <\/select>\n    <\/div>\n\n    <div class=\"r4-ctrl r4-ctrl-sm\">\n      <label class=\"r4-label\" for=\"r4-custom\">Custom size (TB)<\/label>\n      <input type=\"number\" id=\"r4-custom\" class=\"r4-select\" placeholder=\"e.g. 10\" min=\"0.1\" step=\"0.1\" oninput=\"r4Calc()\">\n    <\/div>\n\n    <div class=\"r4-ctrl r4-ctrl-sm\">\n      <label class=\"r4-label\">Drives<\/label>\n      <div class=\"r4-stepper\">\n        <button class=\"r4-sbtn\" onclick=\"r4Step(-1)\" type=\"button\">\u2212<\/button>\n        <span class=\"r4-snum\" id=\"r4-count\">4<\/span>\n        <button class=\"r4-sbtn\" onclick=\"r4Step(1)\"  type=\"button\">+<\/button>\n      <\/div>\n    <\/div>\n\n    <div class=\"r4-ctrl r4-ctrl-sm\">\n      <label class=\"r4-label\" for=\"r4-fs\">Filesystem<\/label>\n      <select id=\"r4-fs\" class=\"r4-select\" onchange=\"r4Calc()\">\n        <option value=\"0\">Raw capacity<\/option>\n        <option value=\"0.075\" selected>ext4 (~7% overhead)<\/option>\n        <option value=\"0.04\">Btrfs (~4%)<\/option>\n        <option value=\"0.04\">ZFS (~4%)<\/option>\n        <option value=\"0.02\">NTFS (~2%)<\/option>\n      <\/select>\n    <\/div>\n\n    <div class=\"r4-ctrl r4-ctrl-sm\">\n      <label class=\"r4-label\">Units<\/label>\n      <div class=\"r4-units\">\n        <button class=\"r4-ubtn active\" id=\"r4-btn-tb\"  onclick=\"r4Unit('tb')\"  type=\"button\">TB<\/button>\n        <button class=\"r4-ubtn\"        id=\"r4-btn-tib\" onclick=\"r4Unit('tib')\" type=\"button\">TiB<\/button>\n      <\/div>\n      <p class=\"r4-unit-hint\">TiB = what your OS shows<\/p>\n    <\/div>\n\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 RAID LEVEL PICKER \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-section\">\n\n    <div id=\"r4-std\" class=\"r4-level-grid\">\n            <div class=\"r4-lvl\" data-level=\"0\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 0<\/div>\n            <div class=\"r4-lvl-sub\">Striping<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-danger\">\u26a1 Max speed<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Full capacity, maximum speed. Zero protection \u2014 one drive failure loses everything.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 2 drives \u00b7 None fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-0\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl r4-active\" data-level=\"1\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 1<\/div>\n            <div class=\"r4-lvl-sub\">Mirroring<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Most reliable<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Every drive is a full mirror. Survives all-but-one failure. Best for critical data.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 2 drives \u00b7 N\u22121 drives fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-1\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"5\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 5<\/div>\n            <div class=\"r4-lvl-sub\">Striping + Parity<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-mid\">\u2696 Most popular<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">One drive lost to parity. Survives 1 failure. Avoid on HDDs larger than 4TB.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 3 drives \u00b7 1 drive fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-5\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"6\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 6<\/div>\n            <div class=\"r4-lvl-sub\">Double Parity<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Business safe<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Two drives lost to parity. Survives 2 simultaneous failures. Best for large HDD arrays.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 4 drives \u00b7 2 drives fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-6\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"10\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 10<\/div>\n            <div class=\"r4-lvl-sub\">Mirror + Stripe<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-mid\">\u26a1 Speed + Safety<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Mirrored pairs, then striped. Best for databases and VMs. Fast rebuild times.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 4 drives \u00b7 1 per pair fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-10\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"50\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 50<\/div>\n            <div class=\"r4-lvl-sub\">RAID 5+0<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-mid\">\u2696 Large arrays<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Two RAID 5 groups striped together. Faster rebuilds than a flat RAID 5.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 6 drives \u00b7 1 per group fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-50\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"60\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">RAID 60<\/div>\n            <div class=\"r4-lvl-sub\">RAID 6+0<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Enterprise<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">Two RAID 6 groups striped. Maximum protection for large enterprise arrays.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 8 drives \u00b7 2 per group fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-60\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"jbod\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\">\n          <div>\n            <div class=\"r4-lvl-name\">JBOD<\/div>\n            <div class=\"r4-lvl-sub\">Spanning<\/div>\n          <\/div>\n          <span class=\"r4-chip r4-chip-danger\">\ud83d\udce6 Max capacity<\/span>\n        <\/div>\n        <p class=\"r4-lvl-desc\">All drives as one volume. No redundancy, no striping. One failure = data loss.<\/p>\n        <div class=\"r4-lvl-foot\">\n          <span class=\"r4-lvl-meta\">Min 1 drives \u00b7 None fault tolerance<\/span>\n          <strong class=\"r4-lvl-cap\" id=\"r4-cap-jbod\">\u2014<\/strong>\n        <\/div>\n      <\/div>\n          <\/div>\n\n    <div id=\"r4-syn\" class=\"r4-level-grid\" style=\"display:none\">\n            <div class=\"r4-lvl r4-active\" data-level=\"shr1\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">SHR-1<\/div><div class=\"r4-lvl-sub\">Hybrid RAID 1<\/div><\/div><span class=\"r4-chip r4-chip-mid\">\u2696 Recommended<\/span><\/div>\n        <p class=\"r4-lvl-desc\">Mixes drive sizes to minimize wasted space. Survives 1 failure. Synology DSM reserves ~10GB per drive.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 2 drives \u00b7 1 drive fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-shr1\">\u2014<\/strong><\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"shr2\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">SHR-2<\/div><div class=\"r4-lvl-sub\">Hybrid RAID 2<\/div><\/div><span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Enterprise<\/span><\/div>\n        <p class=\"r4-lvl-desc\">Double parity for mixed drives. Survives 2 simultaneous failures. Requires 4+ drives.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 4 drives \u00b7 2 drives fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-shr2\">\u2014<\/strong><\/div>\n      <\/div>\n          <\/div>\n\n    <div id=\"r4-unraid\" class=\"r4-level-grid\" style=\"display:none\">\n            <div class=\"r4-lvl r4-active\" data-level=\"unraid1\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">UnRAID<\/div><div class=\"r4-lvl-sub\">Single parity<\/div><\/div><span class=\"r4-chip r4-chip-mid\">\u2696 Standard<\/span><\/div>\n        <p class=\"r4-lvl-desc\">1 parity drive (must be largest). Usable = sum of all data drives. Mix sizes freely.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 2 drives \u00b7 1 drive fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-unraid1\">\u2014<\/strong><\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"unraid2\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">UnRAID +P2<\/div><div class=\"r4-lvl-sub\">Dual parity<\/div><\/div><span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Safe<\/span><\/div>\n        <p class=\"r4-lvl-desc\">2 parity drives. Both must be the largest drives. Survives 2 simultaneous failures.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 3 drives \u00b7 2 drives fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-unraid2\">\u2014<\/strong><\/div>\n      <\/div>\n          <\/div>\n\n    <div id=\"r4-zfs\" class=\"r4-level-grid\" style=\"display:none\">\n            <div class=\"r4-lvl\" data-level=\"raidz1\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">RAIDZ1<\/div><div class=\"r4-lvl-sub\">Single parity ZFS<\/div><\/div><span class=\"r4-chip r4-chip-mid\">\u2696 Standard<\/span><\/div>\n        <p class=\"r4-lvl-desc\">1 parity vdev. Includes 3.1% ZFS slop space. Keep pool below 80% capacity.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 3 drives \u00b7 1 drive fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-raidz1\">\u2014<\/strong><\/div>\n      <\/div>\n            <div class=\"r4-lvl r4-active\" data-level=\"raidz2\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">RAIDZ2<\/div><div class=\"r4-lvl-sub\">Double parity ZFS<\/div><\/div><span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Recommended<\/span><\/div>\n        <p class=\"r4-lvl-desc\">2 parity vdevs. Survives 2 failures. Recommended for TrueNAS SCALE\/CORE.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 4 drives \u00b7 2 drives fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-raidz2\">\u2014<\/strong><\/div>\n      <\/div>\n            <div class=\"r4-lvl\" data-level=\"raidz3\" onclick=\"r4Select(this)\" role=\"button\" tabindex=\"0\">\n        <div class=\"r4-lvl-header\"><div><div class=\"r4-lvl-name\">RAIDZ3<\/div><div class=\"r4-lvl-sub\">Triple parity ZFS<\/div><\/div><span class=\"r4-chip r4-chip-safe\">\ud83d\udee1 Max protection<\/span><\/div>\n        <p class=\"r4-lvl-desc\">3 parity vdevs. Survives 3 simultaneous failures. Enterprise-grade.<\/p>\n        <div class=\"r4-lvl-foot\"><span class=\"r4-lvl-meta\">Min 4 drives \u00b7 3 drives fault tolerance<\/span><strong class=\"r4-lvl-cap\" id=\"r4-cap-raidz3\">\u2014<\/strong><\/div>\n      <\/div>\n          <\/div>\n\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 STATS STRIP \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-stats\">\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Raw storage<\/div><div class=\"r4-stat-v\" id=\"r4-raw\">\u2014<\/div><\/div>\n    <div class=\"r4-stat-div\"><\/div>\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Parity overhead<\/div><div class=\"r4-stat-v\" id=\"r4-ov\">\u2014<\/div><\/div>\n    <div class=\"r4-stat-div\"><\/div>\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Efficiency<\/div><div class=\"r4-stat-v\" id=\"r4-eff\">\u2014<\/div><\/div>\n    <div class=\"r4-stat-div\"><\/div>\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Total drive cost<\/div><div class=\"r4-stat-v\" id=\"r4-cost\">\u2014<\/div><\/div>\n    <div class=\"r4-stat-div\"><\/div>\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Cost per usable TB<\/div><div class=\"r4-stat-v\" id=\"r4-cpt\">\u2014<\/div><\/div>\n    <div class=\"r4-stat-div\"><\/div>\n    <div class=\"r4-stat\"><div class=\"r4-stat-l\">Fault tolerance<\/div><div class=\"r4-stat-v\" id=\"r4-fault\">\u2014<\/div><\/div>\n  <\/div>\n\n  <!-- Rebuild estimate -->\n    <div class=\"r4-rebuild\" id=\"r4-rebuild\" style=\"display:none\">\n    <div class=\"r4-rebuild-inner\">\n      <div class=\"r4-rebuild-icon\">\u23f1<\/div>\n      <div>\n        <p class=\"r4-rebuild-title\">Rebuild time estimate<\/p>\n        <p class=\"r4-rebuild-note\" id=\"r4-rb-note\"><\/p>\n      <\/div>\n      <div class=\"r4-rebuild-vals\">\n        <div class=\"r4-stat\"><div class=\"r4-stat-l\">Estimated time<\/div><div class=\"r4-stat-v\" id=\"r4-rb-time\">\u2014<\/div><\/div>\n        <div class=\"r4-stat\"><div class=\"r4-stat-l\">Risk level<\/div><div class=\"r4-stat-v\" id=\"r4-rb-risk\">\u2014<\/div><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n  \n  <!-- Warnings -->\n    <div id=\"r4-warns\" style=\"display:none\"><\/div>\n  \n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 DRIVE MAP \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-section r4-map-section\">\n    <p class=\"r4-section-label\">Drive layout<\/p>\n    <div class=\"r4-map\" id=\"r4-map\"><\/div>\n    <div class=\"r4-map-legend\">\n      <span class=\"r4-dot r4-dot-d\"><\/span>Data\n      <span class=\"r4-dot r4-dot-p\"><\/span>Parity\n      <span class=\"r4-dot r4-dot-m\"><\/span>Mirror\n    <\/div>\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 COMPARISON TABLE \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-section\">\n    <p class=\"r4-section-label\">All levels compared \u2014 your current configuration<\/p>\n    <div class=\"r4-table-wrap\">\n      <table class=\"r4-table\" aria-label=\"RAID level comparison\">\n        <thead>\n          <tr>\n            <th>Level<\/th><th>Usable capacity<\/th><th>OS reports (TiB)<\/th>\n            <th>Efficiency<\/th><th>Fault tolerance<\/th><th>Cost \/ usable TB<\/th><th>Rebuild risk<\/th>\n          <\/tr>\n        <\/thead>\n        <tbody id=\"r4-tbody\"><\/tbody>\n      <\/table>\n    <\/div>\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 DRIVES \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-section r4-drives-section\">\n    <div class=\"r4-drives-header\">\n      <div>\n        <p class=\"r4-section-label\" style=\"margin:0 0 4px\">Drives for this build<\/p>\n        <p class=\"r4-drives-sub\">Matched to your selected capacity<\/p>\n      <\/div>\n      <span class=\"r4-drives-badge\" id=\"r4-drives-badge\"><\/span>\n    <\/div>\n    <div class=\"r4-drives-grid\" id=\"r4-drives-grid\"><\/div>\n    <div class=\"r4-drives-cta\" id=\"r4-drives-cta\" style=\"display:none\">\n      <div class=\"r4-cta-info\">\n        <strong id=\"r4-cta-name\">\u2014<\/strong>\n        <span id=\"r4-cta-meta\"><\/span>\n      <\/div>\n      <a id=\"r4-cta-link\" href=\"#\" target=\"_blank\" rel=\"sponsored noopener\" class=\"r4-cta-btn\">\n        Buy <span id=\"r4-cta-qty\">4<\/span> drives \u2014 $<span id=\"r4-cta-total\">0<\/span>\n      <\/a>\n    <\/div>\n  <\/div>\n\n  <!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 FOOTER NOTE \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n  <div class=\"r4-footer-note\">\n    <strong>RAID is not a backup.<\/strong> RAID protects against drive failure \u2014 not ransomware, accidental deletion, or physical disasters. Always maintain a separate backup alongside your RAID array.\n  <\/div>\n\n<\/div>\n\n<script>\n(function(){\nvar D=[{\"label\":\"Seagate IronWolf 4TB\",\"tb\":4,\"price\":79,\"asin\":\"B07H289S7C\",\"type\":\"hdd\",\"rpm\":5400,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"Seagate IronWolf 6TB\",\"tb\":6,\"price\":99,\"asin\":\"B01LOOJBQY\",\"type\":\"hdd\",\"rpm\":5400,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"Seagate IronWolf 8TB\",\"tb\":8,\"price\":129,\"asin\":\"B01LOOJBQU\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"Seagate IronWolf 12TB\",\"tb\":12,\"price\":199,\"asin\":\"B07H291F6C\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"Seagate IronWolf 16TB\",\"tb\":16,\"price\":289,\"asin\":\"B07H3WLLYD\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"Seagate IronWolf Pro 20TB\",\"tb\":20,\"price\":399,\"asin\":\"B09YWHDMFJ\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Seagate\"},{\"label\":\"WD Red Plus 4TB\",\"tb\":4,\"price\":74,\"asin\":\"B08TZPS4QQ\",\"type\":\"hdd\",\"rpm\":5400,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red Plus 6TB\",\"tb\":6,\"price\":94,\"asin\":\"B08V18M4KK\",\"type\":\"hdd\",\"rpm\":5400,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red Plus 8TB\",\"tb\":8,\"price\":129,\"asin\":\"B08V174F8P\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red Pro 12TB\",\"tb\":12,\"price\":219,\"asin\":\"B07YFGQN5L\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red Pro 16TB\",\"tb\":16,\"price\":299,\"asin\":\"B08M9TPDMJ\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red SMR 2TB \\u26a0\",\"tb\":2,\"price\":49,\"asin\":\"B084ZTSPV4\",\"type\":\"hdd\",\"rpm\":5400,\"smr\":true,\"brand\":\"WD\"},{\"label\":\"Toshiba N300 4TB\",\"tb\":4,\"price\":69,\"asin\":\"B01LXUH3DM\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Toshiba\"},{\"label\":\"Toshiba N300 8TB\",\"tb\":8,\"price\":119,\"asin\":\"B01LXUH3EV\",\"type\":\"hdd\",\"rpm\":7200,\"smr\":false,\"brand\":\"Toshiba\"},{\"label\":\"Samsung 870 EVO 1TB SSD\",\"tb\":1,\"price\":79,\"asin\":\"B08PC5YWZM\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"Samsung\"},{\"label\":\"Samsung 870 EVO 2TB SSD\",\"tb\":2,\"price\":139,\"asin\":\"B08PC83269\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"Samsung\"},{\"label\":\"Samsung 870 EVO 4TB SSD\",\"tb\":4,\"price\":269,\"asin\":\"B08QBJ2YM9\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"Samsung\"},{\"label\":\"WD Red SA500 1TB SSD\",\"tb\":1,\"price\":89,\"asin\":\"B08565SQLS\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"WD Red SA500 2TB SSD\",\"tb\":2,\"price\":149,\"asin\":\"B08564N1Y3\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"WD\"},{\"label\":\"Seagate IronWolf 110 1.92TB SSD\",\"tb\":1.92,\"price\":199,\"asin\":\"B07KP7KTNR\",\"type\":\"ssd\",\"rpm\":0,\"smr\":false,\"brand\":\"Seagate\"}];\nvar TAG='pccaselab-20';\nvar AMZ_DOMAIN='amazon.com';\nvar SHOW_REBUILD=true;\nvar SHOW_WARNINGS=true;\nvar n=4,lvl='0',platform='standard',unit='tb';\nvar PDESC={standard:'Standard hardware or software RAID. mdadm, Windows Storage Spaces, or a dedicated controller. All drives should be the same size.',synology:'Synology Hybrid RAID divides drives into equal-sized chunks, maximising usable space when mixing different drive sizes. DSM reserves ~10GB per physical drive.',unraid:'UnRAID does not stripe data. Up to 2 drives are dedicated to parity and must be the largest in the array. Usable space = sum of all non-parity drives.',zfs:'ZFS Copy-on-Write filesystem with RAIDZ. Includes 3.125% slop space reservation. Keep the pool below 80% capacity to avoid severe fragmentation.'};\nvar PDEF={standard:'1',synology:'shr1',unraid:'unraid1',zfs:'raidz2'};\n\nfunction amz(asin,qty){return asin?'https:\/\/www.'+AMZ_DOMAIN+'\/dp\/'+asin+'\/?tag='+TAG+'&quantity='+qty:'#';}\n\nfunction fmt(tb){\n  if(tb<=0)return'0 TB';\n  var v=unit==='tib'?tb*0.9094:tb;\n  var s=unit==='tib'?'TiB':'TB';\n  return v>=1?parseFloat(v.toFixed(2))+'\\u202f'+s:parseFloat((v*1000).toFixed(0))+'\\u202fGB';\n}\nfunction fsAdj(tb){return tb*(1-(parseFloat(document.getElementById('r4-fs').value)||0));}\n\nfunction di(){\n  var sel=document.getElementById('r4-drive');\n  var opt=sel.options[sel.selectedIndex];\n  var cst=parseFloat(document.getElementById('r4-custom').value);\n  return{\n    tb:   cst>0?cst:parseFloat(opt.dataset.tb)||4,\n    price:cst>0?0:parseInt(opt.dataset.price)||0,\n    asin: cst>0?'':opt.dataset.asin||'',\n    label:cst>0?(cst+'TB Custom'):opt.text.split(' \u2014 ')[0],\n    type: opt.dataset.type||'hdd',\n    smr:  opt.dataset.smr==='1'\n  };\n}\n\nfunction calc(lv,nd,tb){\n  var u=0,ov=0,ft='None',mn=2;\n  switch(String(lv)){\n    case'0':    u=nd*tb;           ov=0;      ft='None';          mn=2;break;\n    case'1':    u=tb;              ov=(nd-1)*tb;ft=(nd-1)+' drive'+(nd>2?'s':'');mn=2;break;\n    case'5':    u=(nd-1)*tb;       ov=tb;     ft='1 drive';        mn=3;break;\n    case'6':    u=(nd-2)*tb;       ov=2*tb;   ft='2 drives';       mn=4;break;\n    case'10':   u=Math.floor(nd\/2)*tb;ov=Math.ceil(nd\/2)*tb;ft='1 per pair';mn=4;break;\n    case'50':   var g=2,pg=Math.floor(nd\/g);u=(pg-1)*g*tb;ov=g*tb;ft='1 per group';mn=6;break;\n    case'60':   var g2=2,pg2=Math.floor(nd\/g2);u=(pg2-2)*g2*tb;ov=2*g2*tb;ft='2 per group';mn=8;break;\n    case'jbod': u=nd*tb;           ov=0;      ft='None';           mn=1;break;\n    case'shr1': u=Math.max(0,(nd-1)*tb);ov=tb;ft='1 drive';       mn=2;break;\n    case'shr2': u=Math.max(0,(nd-3)*tb);ov=3*tb;ft='2 drives';    mn=4;break;\n    case'unraid1':u=Math.max(0,(nd-1)*tb);ov=tb;ft='1 drive';     mn=2;break;\n    case'unraid2':u=Math.max(0,(nd-2)*tb);ov=2*tb;ft='2 drives';  mn=3;break;\n    case'raidz1':u=(nd-1)*tb*0.96875;ov=tb;  ft='1 drive';        mn=3;break;\n    case'raidz2':u=(nd-2)*tb*0.96875;ov=2*tb;ft='2 drives';       mn=4;break;\n    case'raidz3':u=(nd-3)*tb*0.96875;ov=3*tb;ft='3 drives';       mn=4;break;\n  }\n  u=Math.max(0,u);\n  var raw=nd*tb;\n  return{u,ov,raw,eff:raw>0?Math.round(u\/raw*100):0,ft,mn};\n}\n\nfunction rebuild(tb,type){\n  if(['0','jbod','unraid1','unraid2'].includes(String(lvl)))return null;\n  var spd=type==='ssd'?500:180;\n  var h=(tb*1e6)\/(spd*3600);\n  var risk,note;\n  if(type==='ssd'){risk='\ud83d\udfe2 Low';note='SSDs rebuild in minutes to a few hours. Risk of a second failure during rebuild is minimal.';}\n  else if(tb<=4){risk='\ud83d\udfe1 Moderate';note='Small HDDs rebuild in ~12 hours. Monitor drive health closely throughout.';}\n  else if(tb<=8){risk='\ud83d\udfe0 High';note='8TB HDDs take 15\u201324 hours to rebuild. Risk of URE or second failure is significant \u2014 consider RAID 6.';}\n  else{risk='\ud83d\udd34 Very High';note=tb+'TB HDDs may take 24\u201372 hours to rebuild. Strongly recommend RAID 6 or RAIDZ2 for this drive size.';}\n  h=Math.max(1,Math.round(h));\n  return{time:h<24?h+' hours':Math.round(h\/24)+' days (~'+h+' hrs)',risk,note};\n}\n\nfunction warns(tb,dr){\n  var w=[];\n  var l=String(lvl);\n  if(l==='0'||l==='jbod')w.push({c:'danger',m:'Zero redundancy. A single drive failure means complete, unrecoverable data loss.'});\n  if(l==='5'&&dr.type==='hdd'&&tb>4)w.push({c:'danger',m:'RAID 5 on HDDs larger than 4\\u202fTB is high risk. Rebuilds take 24\u201372 hours. Unrecoverable Read Errors during rebuild can destroy the entire array. Consider upgrading to RAID 6.'});\n  if(dr.smr)w.push({c:'danger',m:'SMR drive detected. SMR drives suffer extreme write latency during RAID rebuilds and are frequently dropped by the controller. Replace with a CMR drive.'});\n  if(['raidz1','raidz2','raidz3'].includes(l))w.push({c:'info',m:'ZFS rule: keep your pool below 80% capacity. Above this threshold, Copy-on-Write fragmentation severely degrades write performance.'});\n  if(l==='shr1')w.push({c:'info',m:'Synology SHR expansion: you must replace at least two drives before the array reports a capacity increase.'});\n  if(l==='unraid1'||l==='unraid2')w.push({c:'info',m:'UnRAID parity rule: parity drive(s) must always be equal to or larger than the largest data drive in the array.'});\n  return w;\n}\n\nfunction buildMap(tb){\n  var vis=Math.min(n,20);\n  var l=String(lvl);\n  var html='';\n  for(var i=0;i<vis;i++){\n    var t='d';\n    if(l==='1')t=i===0?'d':'m';\n    else if(['5','raidz1','shr1','unraid1'].includes(l))t=i===vis-1?'p':'d';\n    else if(['6','raidz2','shr2','unraid2'].includes(l))t=i>=vis-2?'p':'d';\n    else if(l==='raidz3')t=i>=vis-3?'p':'d';\n    else if(l==='10')t=i%2===0?'d':'m';\n    var lb=t==='d'?'D'+(i+1):t==='p'?'P':'M'+(i+1);\n    html+='<div class=\"r4-block r4-block-'+t+'\"><div class=\"r4-block-l\">'+lb+'<\/div><div class=\"r4-block-s\">'+fmt(tb)+'<\/div><\/div>';\n  }\n  if(n>20)html+='<div class=\"r4-block-more\">+' +(n-20)+' more<\/div>';\n  document.getElementById('r4-map').innerHTML=html;\n}\n\nfunction buildTable(tb,price){\n  var sets,names,use;\n  if(platform==='synology'){sets=['shr1','shr2'];names={shr1:'SHR-1',shr2:'SHR-2'};use={shr1:'Home NAS',shr2:'Business NAS'};}\n  else if(platform==='unraid'){sets=['unraid1','unraid2'];names={unraid1:'UnRAID 1P',unraid2:'UnRAID 2P'};use={unraid1:'Media server',unraid2:'Critical data'};}\n  else if(platform==='zfs'){sets=['raidz1','raidz2','raidz3'];names={raidz1:'RAIDZ1',raidz2:'RAIDZ2',raidz3:'RAIDZ3'};use={raidz1:'General NAS',raidz2:'TrueNAS',raidz3:'Enterprise'};}\n  else{sets=['0','1','5','6','10','50','60','jbod'];names={'0':'RAID 0','1':'RAID 1','5':'RAID 5','6':'RAID 6','10':'RAID 10','50':'RAID 50','60':'RAID 60','jbod':'JBOD'};use={'0':'Scratch','1':'Critical','5':'Home NAS','6':'Business','10':'DB\/VMs','50':'Large','60':'Enterprise','jbod':'Max capacity'};}\n  var risks={'0':'\u2014','1':'\ud83d\udfe2 Low','5':tb>4?'\ud83d\udd34 Very High':'\ud83d\udfe1 Moderate','6':'\ud83d\udfe0 High','10':'\ud83d\udfe2 Low','50':'\ud83d\udfe0 High','60':'\ud83d\udfe0 High','jbod':'\u2014','shr1':'\ud83d\udfe1 Moderate','shr2':'\ud83d\udfe0 High','unraid1':'\u2014','unraid2':'\u2014','raidz1':'\ud83d\udfe1 Moderate','raidz2':'\ud83d\udfe0 High','raidz3':'\ud83d\udfe0 High'};\n  document.getElementById('r4-tbody').innerHTML=sets.map(function(lv){\n    var r=calc(lv,n,tb);var dis=n<r.mn;var act=String(lvl)===String(lv);\n    var cpt=price>0&&r.u>0?'$'+Math.round(n*price\/r.u)+'\/TB':'\u2014';\n    var tib=dis?'\u2014':parseFloat((r.u*0.9094).toFixed(2))+' TiB';\n    return'<tr class=\"'+(act?'r4-tr-act':'')+(dis?' r4-tr-dim':'')+'\"><td><strong>'+(names[lv]||lv)+'<\/strong><\/td><td>'+(dis?'Need '+r.mn+'+':fmt(fsAdj(r.u)))+'<\/td><td>'+tib+'<\/td><td>'+(dis?'\u2014':r.eff+'%')+'<\/td><td>'+r.ft+'<\/td><td>'+cpt+'<\/td><td>'+(risks[lv]||'\u2014')+'<\/td><\/tr>';\n  }).join('');\n}\n\nfunction buildDrives(tb,nd,price,asin,label){\n  var sim=D.filter(function(d){return Math.abs(d.tb-tb)<=2;}).slice(0,4);\n  if(!sim.length)sim=D.slice(0,4);\n  document.getElementById('r4-drives-badge').textContent=sim.length+' drives matched';\n  document.getElementById('r4-drives-grid').innerHTML=sim.map(function(d){\n    var lk=amz(d.asin,nd);\n    var smrW=d.smr?'<span class=\"r4-drive-smr\">\u26a0 SMR \u2014 not recommended for RAID<\/span>':'';\n    return'<div class=\"r4-drive-card\">'\n      +'<div class=\"r4-drive-top\"><span class=\"r4-drive-type r4-dtype-'+(d.type==='ssd'?'ssd':'hdd')+'\">'+d.type.toUpperCase()+'<\/span>'+smrW+'<\/div>'\n      +'<div class=\"r4-drive-name\">'+d.label+'<\/div>'\n      +'<div class=\"r4-drive-meta\">'+d.tb+' TB'+(d.rpm?' \u00b7 '+d.rpm+' RPM':' \u00b7 SATA SSD')+(d.smr?' \u00b7 SMR':' \u00b7 CMR')+'<\/div>'\n      +'<div class=\"r4-drive-price-row\">'\n        +'<div><div class=\"r4-dp\">$'+d.price+'<\/div><div class=\"r4-dp-l\">per drive<\/div><\/div>'\n        +'<div><div class=\"r4-dp\">$'+(d.price*nd)+'<\/div><div class=\"r4-dp-l\">\u00d7'+nd+' drives<\/div><\/div>'\n      +'<\/div>'\n      +(d.asin?'<a href=\"'+lk+'\" target=\"_blank\" rel=\"sponsored noopener\" class=\"r4-drive-btn\">Check price on Amazon \u2197<\/a>':'<div class=\"r4-drive-btn r4-drive-na\">Custom size<\/div>')\n      +'<\/div>';\n  }).join('');\n  var cta=document.getElementById('r4-drives-cta');\n  if(asin&&price>0){\n    cta.style.display='flex';\n    document.getElementById('r4-cta-name').textContent=label;\n    document.getElementById('r4-cta-meta').textContent='$'+price+' each';\n    document.getElementById('r4-cta-qty').textContent=nd;\n    document.getElementById('r4-cta-link').href=amz(asin,nd);\n    document.getElementById('r4-cta-total').textContent=(price*nd).toLocaleString();\n  }else{cta.style.display='none';}\n}\n\nfunction updateCards(tb){\n  var all=['0','1','5','6','10','50','60','jbod','shr1','shr2','unraid1','unraid2','raidz1','raidz2','raidz3'];\n  all.forEach(function(lv){\n    var el=document.getElementById('r4-cap-'+lv);if(!el)return;\n    var r=calc(lv,n,tb);\n    if(n<r.mn){el.textContent='Need '+r.mn+'+ drives';el.className='r4-lvl-cap r4-cap-na';}\n    else{el.textContent=fmt(fsAdj(r.u));el.className='r4-lvl-cap';}\n  });\n}\n\nwindow.r4Calc=function(){\n  var dr=di();var r=calc(lvl,n,dr.tb);var adj=fsAdj(r.u);\n\n  \/\/ Hero\n  var heroNum=document.getElementById('r4-hero-num');\n  var heroSub=document.getElementById('r4-hero-sub');\n  if(n<r.mn){\n    heroNum.textContent='\u2014';\n    heroSub.textContent='Need at least '+r.mn+' drives for this level';\n  }else{\n    heroNum.textContent=fmt(adj);\n    heroSub.textContent='Raw '+fmt(r.raw)+' \u00b7 OS reports ~'+parseFloat((adj*0.9094).toFixed(2))+' TiB \u00b7 '+r.eff+'% efficient';\n  }\n\n  \/\/ Pills\n  var pills=document.getElementById('r4-result-pills');\n  pills.innerHTML=[\n    r.ft!=='None'?'<span class=\"r4-pill r4-pill-green\">'+r.ft+' fault tolerance<\/span>':'<span class=\"r4-pill r4-pill-red\">No redundancy<\/span>',\n    dr.price>0&&r.u>0?'<span class=\"r4-pill\">$'+Math.round(n*dr.price\/r.u)+'\/usable TB<\/span>':'',\n    '<span class=\"r4-pill\">'+n+'\u00d7 '+dr.tb+'TB<\/span>'\n  ].join('');\n\n  \/\/ Stats\n  document.getElementById('r4-raw').textContent=fmt(r.raw);\n  document.getElementById('r4-ov').textContent=fmt(r.ov);\n  document.getElementById('r4-eff').textContent=r.eff+'%';\n  document.getElementById('r4-fault').textContent=r.ft;\n  if(dr.price>0){\n    document.getElementById('r4-cost').textContent='$'+(n*dr.price).toLocaleString();\n    document.getElementById('r4-cpt').textContent=r.u>0?'$'+Math.round(n*dr.price\/r.u)+'\/TB':'\u2014';\n  }else{document.getElementById('r4-cost').textContent='\u2014';document.getElementById('r4-cpt').textContent='\u2014';}\n\n  \/\/ Rebuild\n  var rbEl=document.getElementById('r4-rebuild');\n  if(SHOW_REBUILD&&rbEl){\n    var rb=rebuild(dr.tb,dr.type);\n    if(rb&&n>=r.mn){\n      rbEl.style.display='block';\n      document.getElementById('r4-rb-time').textContent=rb.time;\n      document.getElementById('r4-rb-risk').textContent=rb.risk;\n      document.getElementById('r4-rb-note').textContent=rb.note;\n    }else{rbEl.style.display='none';}\n  }\n\n  \/\/ Warnings\n  var wEl=document.getElementById('r4-warns');\n  if(SHOW_WARNINGS&&wEl){\n    var ws=warns(dr.tb,dr);\n    if(ws.length){\n      wEl.style.display='block';\n      wEl.innerHTML='<div class=\"r4-warns-inner\">'+ws.map(function(w){return'<div class=\"r4-warn r4-warn-'+w.c+'\">'+w.m+'<\/div>';}).join('')+'<\/div>';\n    }else{wEl.style.display='none';}\n  }\n\n  updateCards(dr.tb);\n  buildMap(dr.tb);\n  buildTable(dr.tb,dr.price);\n  buildDrives(dr.tb,n,dr.price,dr.asin,dr.label);\n};\n\nwindow.r4Step=function(d){\n  n=Math.max(1,Math.min(24,n+d));\n  document.getElementById('r4-count').textContent=n;\n  r4Calc();\n};\n\nwindow.r4Select=function(card){\n  document.querySelectorAll('.r4-lvl').forEach(function(c){c.classList.remove('r4-active');});\n  card.classList.add('r4-active');\n  lvl=card.dataset.level;\n  r4Calc();\n};\n\nwindow.r4Platform=function(btn){\n  document.querySelectorAll('.r4-tab').forEach(function(b){b.classList.remove('active');});\n  btn.classList.add('active');\n  platform=btn.dataset.p;\n  document.getElementById('r4-tab-desc').textContent=PDESC[platform];\n  ['r4-std','r4-syn','r4-unraid','r4-zfs'].forEach(function(id){var el=document.getElementById(id);if(el)el.style.display='none';});\n  var map={standard:'r4-std',synology:'r4-syn',unraid:'r4-unraid',zfs:'r4-zfs'};\n  var el=document.getElementById(map[platform]);if(el)el.style.display='grid';\n  lvl=PDEF[platform];\n  document.querySelectorAll('.r4-lvl').forEach(function(c){c.classList.remove('r4-active');});\n  var first=el&&el.querySelector('[data-level=\"'+lvl+'\"]');\n  if(first)first.classList.add('r4-active');\n  r4Calc();\n};\n\nwindow.r4Unit=function(u){\n  unit=u;\n  document.getElementById('r4-btn-tb').classList.toggle('active',u==='tb');\n  document.getElementById('r4-btn-tib').classList.toggle('active',u==='tib');\n  r4Calc();\n};\n\n\/\/ Sync the UI to the admin-configured defaults (platform tab, level card, drive count)\n(function r4ApplyDefaults(){\n  document.getElementById('r4-count').textContent=n;\n\n  document.querySelectorAll('.r4-tab').forEach(function(b){\n    b.classList.toggle('active', b.dataset.p===platform);\n  });\n  document.getElementById('r4-tab-desc').textContent=PDESC[platform]||'';\n\n  var map={standard:'r4-std',synology:'r4-syn',unraid:'r4-unraid',zfs:'r4-zfs'};\n  Object.keys(map).forEach(function(p){\n    var el=document.getElementById(map[p]);\n    if(el)el.style.display=(p===platform)?'grid':'none';\n  });\n\n  document.querySelectorAll('.r4-lvl').forEach(function(c){\n    c.classList.toggle('r4-active', c.dataset.level===String(lvl));\n  });\n})();\n\nr4Calc();\n})();\n<\/script>\n<\/div>\n  <p class=\"pcl-calc-disclaimer\">RAID is not a backup. RAID protects against drive failure &mdash; not ransomware, accidental deletion, or physical disasters. Always maintain a separate backup alongside your RAID array.<\/p>\n<\/section>\n<\/div>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\"><\/div>\n<\/div>\n\n\n\n<style>\n.pcl-raid{--ink:#15141b;--ink-soft:#5b5866;--bg:#f8f9fb;--surface:#fff;--surface-2:#eef0f4;--border:#e2e5ec;--accent:#6d4fd6;--accent-hover:#5a3fc0;--accent-soft:#efe9fb;--accent-ink:#5a3fc0;--steel:#3d5a80;--radius:16px;--sans:'Manrope',-apple-system,'Segoe UI',sans-serif;--mono:'IBM Plex Mono',ui-monospace,monospace;--container:1180px;font-family:var(--sans);color:var(--ink);background:var(--bg);line-height:1.55;}\n.pcl-raid *{box-sizing:border-box;}\n.pcl-raid a{color:inherit;text-decoration:none;}\n.pcl-raid img{max-width:100%;height:auto;display:block;}\n.pcl-raid .pcl-wrap{max-width:var(--container);margin:0 auto;padding-left:28px;padding-right:28px;}\n.pcl-raid .pcl-wrap--narrow{max-width:820px;}\n.pcl-raid .pcl-wrap--mid{max-width:1000px;}\n.pcl-raid .pcl-section{padding:56px 0;}\n.pcl-raid .pcl-section--bordered{border-top:1px solid var(--border);border-bottom:1px solid var(--border);background:var(--surface);}\n.pcl-raid .pcl-eyebrow{font-family:var(--mono);text-transform:uppercase;letter-spacing:.1em;font-size:11.5px;font-weight:600;color:var(--accent-ink);margin:0 0 10px;}\n.pcl-raid .pcl-h2{font-size:clamp(1.5rem,2.8vw,1.9rem);letter-spacing:-.01em;margin:0 0 24px;font-weight:800;color:var(--ink);}\n.pcl-raid .pcl-body p{font-size:.98rem;color:var(--ink);line-height:1.8;margin:0 0 16px;}\n.pcl-raid .pcl-body a{color:var(--accent-ink);text-decoration:underline;}\n.pcl-raid .pcl-body a:hover{color:var(--ink);}\n\n\/* diagram placeholder *\/\n.pcl-raid .pcl-diagram{aspect-ratio:16\/9;border-radius:12px;border:1px solid var(--border);background:linear-gradient(135deg,var(--surface-2),var(--surface));display:flex;align-items:center;justify-content:center;overflow:hidden;}\n.pcl-raid .pcl-diagram span{font-family:var(--mono);font-size:10.5px;letter-spacing:.06em;color:var(--ink-soft);text-transform:uppercase;}\n.pcl-raid .pcl-diagram img{width:100%;height:100%;object-fit:cover;margin:0;}\n\n\/* responsive data table (css grid rows) *\/\n.pcl-raid .pcl-table-wrap{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius);overflow-x:auto;}\n.pcl-raid .pcl-table{display:grid;grid-template-columns:1.1fr .9fr .9fr .8fr;width:100%;min-width:600px;}\n.pcl-raid .pcl-table--cost{grid-template-columns:1fr 1fr 1fr 1.2fr;}\n.pcl-raid .pcl-table-head{font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:.06em;color:var(--ink-soft);font-weight:600;padding:12px 14px;border-bottom:1px solid var(--border);}\n.pcl-raid .pcl-table-cell{padding:14px;border-bottom:1px solid var(--border);display:flex;align-items:center;font-size:.85rem;color:var(--ink-soft);}\n.pcl-raid .pcl-table-cell--strong{font-weight:700;font-size:.88rem;color:var(--ink);}\n.pcl-raid .pcl-table-cell--mono{font-family:var(--mono);font-size:.82rem;color:var(--ink);}\n.pcl-raid .pcl-table-cell--accent{font-family:var(--mono);font-size:.85rem;color:var(--accent-ink);}\n.pcl-raid .pcl-table-foot{font-size:.85rem;color:var(--ink-soft);margin:18px 0 0;line-height:1.7;}\n\n\/* grid cards *\/\n.pcl-raid .pcl-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:16px;}\n.pcl-raid .pcl-grid--use{grid-template-columns:repeat(auto-fit,minmax(260px,1fr));}\n.pcl-raid .pcl-grid--summary{grid-template-columns:repeat(auto-fit,minmax(240px,1fr));}\n.pcl-raid .pcl-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:22px;display:flex;flex-direction:column;gap:8px;}\n.pcl-raid .pcl-card h3{font-size:1rem;margin:0;font-weight:700;color:var(--ink);}\n.pcl-raid .pcl-card p{font-size:.86rem;color:var(--ink-soft);margin:0;line-height:1.65;}\n.pcl-raid .pcl-card-formula{font-family:var(--mono);font-size:.92rem;color:var(--accent-ink);margin:0;font-weight:600;}\n.pcl-raid .pcl-card-number{font-family:var(--mono);font-weight:600;font-size:1.3rem;color:var(--accent);opacity:.5;}\n\n\/* steps *\/\n.pcl-raid .pcl-steps{display:flex;flex-direction:column;gap:22px;}\n.pcl-raid .pcl-step{display:flex;gap:18px;align-items:flex-start;}\n.pcl-raid .pcl-step-num{flex:0 0 auto;width:32px;height:32px;border-radius:50%;background:var(--accent-soft);color:var(--accent-ink);font-family:var(--mono);font-weight:700;font-size:.9rem;display:flex;align-items:center;justify-content:center;}\n.pcl-raid .pcl-step h3{font-size:1rem;margin:0 0 6px;font-weight:700;color:var(--ink);}\n.pcl-raid .pcl-step p{font-size:.9rem;color:var(--ink-soft);margin:0;line-height:1.65;}\n\n\/* use case cards with media *\/\n.pcl-raid .pcl-use-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;transition:border-color .2s;}\n.pcl-raid .pcl-use-card:hover{border-color:var(--accent);}\n.pcl-raid .pcl-use-media{aspect-ratio:16\/10;background:linear-gradient(135deg,var(--surface-2),var(--surface));display:flex;align-items:center;justify-content:center;overflow:hidden;}\n.pcl-raid .pcl-use-media span{font-family:var(--mono);font-size:9.5px;letter-spacing:.06em;color:var(--ink-soft);text-transform:uppercase;}\n.pcl-raid .pcl-use-media img{width:100%;height:100%;object-fit:cover;margin:0;}\n.pcl-raid .pcl-use-body{padding:20px;display:flex;flex-direction:column;gap:8px;}\n.pcl-raid .pcl-use-tag{font-family:var(--mono);font-size:10px;text-transform:uppercase;letter-spacing:.05em;color:var(--accent-ink);font-weight:600;}\n.pcl-raid .pcl-use-body h3{font-size:1rem;margin:0;font-weight:700;color:var(--ink);}\n.pcl-raid .pcl-use-body p{font-size:.86rem;color:var(--ink-soft);margin:0;line-height:1.65;}\n\n\/* callout *\/\n.pcl-raid .pcl-callout{background:var(--accent-soft);border:1px solid var(--border);border-radius:var(--radius);padding:26px 28px;}\n.pcl-raid .pcl-callout h3{font-size:1.05rem;margin:0 0 10px;font-weight:800;color:var(--ink);}\n.pcl-raid .pcl-callout p{font-size:.92rem;color:var(--ink);margin:0;line-height:1.75;}\n.pcl-raid .pcl-callout a{color:var(--accent-ink);text-decoration:underline;}\n\n\/* compare columns *\/\n.pcl-raid .pcl-compare-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:24px;}\n.pcl-raid .pcl-compare-col h3{font-size:1.15rem;margin:0 0 12px;font-weight:800;color:var(--ink);}\n.pcl-raid .pcl-compare-col p{font-size:.92rem;color:var(--ink);line-height:1.75;margin:0;}\n\n\/* faq *\/\n.pcl-raid .pcl-faq-list{display:flex;flex-direction:column;gap:22px;}\n.pcl-raid .pcl-faq-item h3{font-size:1rem;margin:0 0 6px;font-weight:700;color:var(--ink);}\n.pcl-raid .pcl-faq-item p{font-size:.9rem;color:var(--ink-soft);margin:0;line-height:1.7;}\n\n\/* bridge links *\/\n.pcl-raid .pcl-bridge-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:18px;}\n.pcl-raid .pcl-bridge-card{background:var(--surface-2);border:1px solid var(--border);border-radius:var(--radius);padding:24px;display:flex;flex-direction:column;gap:6px;transition:border-color .2s;}\n.pcl-raid .pcl-bridge-card:hover{border-color:var(--accent);}\n.pcl-raid .pcl-bridge-card strong{font-size:.95rem;font-weight:700;color:var(--ink);}\n.pcl-raid .pcl-bridge-card span{font-size:.85rem;color:var(--ink-soft);}\n\n@media (max-width:640px){.pcl-raid .pcl-section{padding:40px 0;}}\n<\/style>\n\n<div class=\"pcl-raid\">\n\n<section class=\"pcl-section\" style=\"padding-top:0;\">\n  <div class=\"pcl-wrap pcl-wrap--narrow pcl-body\">\n    <p class=\"pcl-eyebrow\">Overview<\/p>\n    <h2 class=\"pcl-h2\">RAID Disk Space Calculator: Determine Your RAID Configuration<\/h2>\n    <p>The RAID disk space calculator calculates the usable capacity based upon the total raw capacity of your disks after considering the redundancy overhead. Total raw capacity is the aggregate of all disks. In addition, the usable capacity is the amount of writable space remaining after allocating space for parity, mirroring, or striping within the RAID controller.<\/p>\n    <p style=\"margin-bottom:28px;\">For example, if you use four 8TB disks in RAID 5, you&#8217;d have 32TB of raw capacity, but approximately 24TB of usable capacity. The 8TB difference isn&#8217;t &ldquo;waste&rdquo; &mdash; it&#8217;s the additional layer of fault tolerance protecting your storage pool from becoming unavailable due to a failed disk.<\/p>\n    <div class=\"pcl-diagram\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/raw-vs.-usable-capacity-by-RAID-level-scaled.webp\" alt=\"RAID Configuration NAS Raw Vs Usable\" loading=\"lazy\"><\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section pcl-section--bordered\">\n  <div class=\"pcl-wrap pcl-wrap--mid\">\n    <p class=\"pcl-eyebrow\">Reference<\/p>\n    <h2 class=\"pcl-h2\">RAID Levels at a Glance<\/h2>\n    <div class=\"pcl-table-wrap\">\n      <div class=\"pcl-table\">\n        <div class=\"pcl-table-head\">RAID Level<\/div>\n        <div class=\"pcl-table-head\">Min. Drives<\/div>\n        <div class=\"pcl-table-head\">Usable Capacity<\/div>\n        <div class=\"pcl-table-head\">Fault Tolerance<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 0<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">2<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">n &times; drive_size<\/div>\n        <div class=\"pcl-table-cell\">0<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 1<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">2<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">1 &times; drive_size<\/div>\n        <div class=\"pcl-table-cell\">n-1<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 1E<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">3<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">~50% of raw<\/div>\n        <div class=\"pcl-table-cell\">1<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 5<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">3<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">(n-1) &times; drive_size<\/div>\n        <div class=\"pcl-table-cell\">1<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 6<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">4<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">(n-2) &times; drive_size<\/div>\n        <div class=\"pcl-table-cell\">2<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 10<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">4 (even)<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">50% of raw<\/div>\n        <div class=\"pcl-table-cell\">1 per mirror pair<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 50<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">6<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">Varies by group<\/div>\n        <div class=\"pcl-table-cell\">1 per RAID 5 group<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 60<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">8<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">Varies by group<\/div>\n        <div class=\"pcl-table-cell\">2 per RAID 6 group<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">JBOD<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">1<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--mono\">100% of all disks<\/div>\n        <div class=\"pcl-table-cell\">0<\/div>\n      <\/div>\n    <\/div>\n    <p class=\"pcl-table-foot\">RAID levels 10, 50, and 60 require an even number of drives. RAID 50 and 60 additionally require a minimum of six and eight disks respectively, grouped as sub-arrays. These levels are standardized by the Storage Networking Industry Association (SNIA) under the Common RAID Disk Drive Format specification.<\/p>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section\">\n  <div class=\"pcl-wrap pcl-wrap--mid\">\n    <p class=\"pcl-eyebrow\">Calculations<\/p>\n    <h2 class=\"pcl-h2\">Utilizing a RAID Disk Space Calculator<\/h2>\n    <div class=\"pcl-grid\">\n      <div class=\"pcl-card\">\n        <h3>RAID 5 &mdash; Striping + Parity<\/h3>\n        <p class=\"pcl-card-formula\">(n &minus; 1) &times; disk_size<\/p>\n        <p>Distributes parity across all drives. Three 8TB drives yield 16TB usable; six yield 40TB. Survives one drive failure &mdash; a second failure during rebuild takes down the array.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <h3>RAID 6 &mdash; Double Parity<\/h3>\n        <p class=\"pcl-card-formula\">(n &minus; 2) &times; disk_size<\/p>\n        <p>Six 12TB drives yield 48TB usable with two-failure tolerance. The bare-minimum recommendation for arrays using HDDs larger than 4TB, where rebuilds can take 15&ndash;72 hours.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <h3>RAID 10 &mdash; Mirror + Stripe<\/h3>\n        <p class=\"pcl-card-formula\">50% of raw capacity<\/p>\n        <p>Mirrored pairs, striped together. Four 10TB NVMe disks yield 20TB usable with the best sequential read\/write of any redundant RAID level &mdash; the default for database and AI\/ML workloads.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <h3>RAID 0 &mdash; Striping Only<\/h3>\n        <p class=\"pcl-card-formula\">n &times; drive_size<\/p>\n        <p>No redundancy, 100% of capacity used. Maximizes bandwidth but a single drive failure destroys all data. Use only for scratch storage or temporary caches.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <h3>RAID 50 &mdash; RAID 5+0 Nested<\/h3>\n        <p class=\"pcl-card-formula\">Varies by group<\/p>\n        <p>Configures disks as RAID 5 sub-arrays, striped together. Six 8TB disks in two groups yield 32TB usable, with faster rebuilds than one flat six-disk RAID 5.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <h3>RAID 60 &mdash; RAID 6+0 Nested<\/h3>\n        <p class=\"pcl-card-formula\">Varies by group<\/p>\n        <p>RAID 6 sub-arrays striped together. Eight 20TB disks in two groups yield 80TB usable with double-parity protection per group &mdash; common on enterprise 10GbE backup servers.<\/p>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section pcl-section--bordered\">\n  <div class=\"pcl-wrap pcl-wrap--narrow\">\n    <p class=\"pcl-eyebrow\">How to Use<\/p>\n    <h2 class=\"pcl-h2\">Steps for Using the Calculator<\/h2>\n    <div class=\"pcl-steps\">\n      <div class=\"pcl-step\">\n        <span class=\"pcl-step-num\">1<\/span>\n        <div><h3>Select drives<\/h3><p>Enter total disk count and capacity in TB (use the labeled drive capacity, not OS-reported TiB).<\/p><\/div>\n      <\/div>\n      <div class=\"pcl-step\">\n        <span class=\"pcl-step-num\">2<\/span>\n        <div><h3>Choose RAID type<\/h3><p>Pick based on your fault tolerance and performance requirements.<\/p><\/div>\n      <\/div>\n      <div class=\"pcl-step\">\n        <span class=\"pcl-step-num\">3<\/span>\n        <div><h3>Verify usable capacity<\/h3><p>This is your actual writable storage space, after parity\/mirroring overhead.<\/p><\/div>\n      <\/div>\n      <div class=\"pcl-step\">\n        <span class=\"pcl-step-num\">4<\/span>\n        <div><h3>Consider the OS gap<\/h3><p>Windows and Linux read storage in binary &mdash; a labeled 10TB drive displays as about 9.09TiB, roughly 9% less than the decimal value.<\/p><\/div>\n      <\/div>\n      <div class=\"pcl-step\">\n        <span class=\"pcl-step-num\">5<\/span>\n        <div><h3>Designate a hot spare<\/h3><p>If your controller supports it, a hot spare automatically replaces a failed disk and begins recovery with no manual action.<\/p><\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section\">\n  <div class=\"pcl-wrap\">\n    <p class=\"pcl-eyebrow\">Use Cases<\/p>\n    <h2 class=\"pcl-h2\">Real-World Examples by RAID Level<\/h2>\n    <div class=\"pcl-grid pcl-grid--use\">\n      <div class=\"pcl-use-card\">\n        <div class=\"pcl-use-media\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/home-nas.webp\" alt=\"home nas\" loading=\"lazy\"><\/div>\n        <div class=\"pcl-use-body\">\n          <span class=\"pcl-use-tag\">3&ndash;5 drives<\/span>\n          <h3>Home NAS<\/h3>\n          <p>RAID 5 is the most common choice &mdash; four 8TB NAS drives give 24TB usable with one-drive failure protection, ideal for a media server or personal backup.<\/p>\n        <\/div>\n      <\/div>\n      <div class=\"pcl-use-card\">\n        <div class=\"pcl-use-media\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/SmallMedium-Business-scaled.webp\" alt=\"SmallMedium Business\" loading=\"lazy\"><\/div>\n        <div class=\"pcl-use-body\">\n          <span class=\"pcl-use-tag\">4&ndash;8 drives<\/span>\n          <h3>Small\/Medium Business<\/h3>\n          <p>RAID 6 on NAS HDD or SSD protects against two simultaneous failures. Six 12TB drives give 48TB usable with no catastrophic loss risk mid-rebuild.<\/p>\n        <\/div>\n      <\/div>\n      <div class=\"pcl-use-card\">\n        <div class=\"pcl-use-media\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/Performance-Workload-scaled.webp\" alt=\"Performance Workload\" loading=\"lazy\"><\/div>\n        <div class=\"pcl-use-body\">\n          <span class=\"pcl-use-tag\">Performance<\/span>\n          <h3>Performance Workload<\/h3>\n          <p>RAID 10 with NVMe SSDs is the top performer for IOPS and rebuild speed &mdash; four drives give 50% usable capacity with near-RAID 0 speed and RAID 1 resilience.<\/p>\n        <\/div>\n      <\/div>\n      <div class=\"pcl-use-card\">\n        <div class=\"pcl-use-media\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/Enterprise-SAN-Data-Centers-scaled.webp\" alt=\"Enterprise SAN Data Centers\" loading=\"lazy\"><\/div>\n        <div class=\"pcl-use-body\">\n          <span class=\"pcl-use-tag\">Enterprise<\/span>\n          <h3>Enterprise SAN &amp; Data Centers<\/h3>\n          <p>RAID 60 across 8&ndash;12 enterprise HDDs provides distributed performance with double parity per group &mdash; critical when simultaneous failures are a real risk.<\/p>\n        <\/div>\n      <\/div>\n      <div class=\"pcl-use-card\">\n        <div class=\"pcl-use-media\"><img decoding=\"async\" src=\"https:\/\/pccaselab.com\/test\/wp-content\/uploads\/2026\/07\/AV-Network-Content-Production-scaled.webp\" alt=\"AV Network Content Production\" loading=\"lazy\"><\/div>\n        <div class=\"pcl-use-body\">\n          <span class=\"pcl-use-tag\">Content Production<\/span>\n          <h3>AV Network &amp; Content Production<\/h3>\n          <p>RAID 5 and RAID 10 with SSD arrays handle multi-stream video editing, where storage bandwidth matters more than raw disk count.<\/p>\n        <\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section\" style=\"padding-top:0;\">\n  <div class=\"pcl-wrap pcl-wrap--narrow\">\n    <div class=\"pcl-callout\">\n      <h3>Mixing Drive Sizes: What You Must Understand<\/h3>\n      <p>All standard RAID levels treat all drives equally regardless of individual capacities &mdash; adding a 4TB and an 8TB drive together permanently wastes the unused capacity of the larger drive. Platforms such as Synology SHR and UnRAID allow mismatched drive capacities without creating waste, ideal for expanding a <a href=\"\/best-raid-for-nas\">NAS storage pool<\/a> over time by swapping in larger drives incrementally.<\/p>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section pcl-section--bordered\">\n  <div class=\"pcl-wrap pcl-wrap--narrow\">\n    <p class=\"pcl-eyebrow\">Cost Analysis<\/p>\n    <h2 class=\"pcl-h2\">Usable vs. Raw Capacity Ratio<\/h2>\n    <p style=\"font-size:.94rem;color:var(--ink-soft);margin:0 0 24px;line-height:1.7;\">Example based on four 8TB drives (8TB &times; 4 = 32TB raw):<\/p>\n    <div class=\"pcl-table-wrap\">\n      <div class=\"pcl-table pcl-table--cost\">\n        <div class=\"pcl-table-head\">RAID Level<\/div>\n        <div class=\"pcl-table-head\">Raw (4&times;8TB)<\/div>\n        <div class=\"pcl-table-head\">Usable<\/div>\n        <div class=\"pcl-table-head\">Efficiency<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 5<\/div>\n        <div class=\"pcl-table-cell\">32 TB<\/div>\n        <div class=\"pcl-table-cell\" style=\"font-weight:600;color:var(--ink);\">24 TB<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--accent\">75%<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 6<\/div>\n        <div class=\"pcl-table-cell\">32 TB<\/div>\n        <div class=\"pcl-table-cell\" style=\"font-weight:600;color:var(--ink);\">16 TB<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--accent\">50%<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 10<\/div>\n        <div class=\"pcl-table-cell\">32 TB<\/div>\n        <div class=\"pcl-table-cell\" style=\"font-weight:600;color:var(--ink);\">16 TB<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--accent\">50%<\/div>\n\n        <div class=\"pcl-table-cell pcl-table-cell--strong\">RAID 0<\/div>\n        <div class=\"pcl-table-cell\">32 TB<\/div>\n        <div class=\"pcl-table-cell\" style=\"font-weight:600;color:var(--ink);\">32 TB<\/div>\n        <div class=\"pcl-table-cell pcl-table-cell--accent\">100% (no protection)<\/div>\n      <\/div>\n    <\/div>\n    <p class=\"pcl-table-foot\" style=\"margin-top:20px;\">RAID 5 offers the best cost-per-usable-TB for arrays up to five or six drives. RAID 6 and RAID 10 both offer stronger redundancy &mdash; RAID 6 through double parity, RAID 10 through mirroring with a speed gain &mdash; but each requires roughly double the storage overhead of RAID 5.<\/p>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section\">\n  <div class=\"pcl-wrap pcl-wrap--mid pcl-compare-grid\">\n    <div class=\"pcl-compare-col\">\n      <p class=\"pcl-eyebrow\">Comparison<\/p>\n      <h3>RAID vs. JBOD<\/h3>\n      <p>JBOD, a non-RAID storage option, uses every available bit of disk capacity &mdash; no overhead, no protection. It concatenates drives into one volume or uses them independently. Use JBOD only when data is backed up separately or loss would be acceptable: archival drives, test environments, secondary storage. Unlike any RAID array, JBOD has zero data-recovery options when a disk fails.<\/p>\n    <\/div>\n    <div class=\"pcl-compare-col\">\n      <p class=\"pcl-eyebrow\">Best Practices<\/p>\n      <h3>Configuring Hot Spares<\/h3>\n      <p>A hot spare sits idle on a RAID controller until a disk fails, then automatically steps in and begins rebuilding &mdash; zero downtime, zero manual intervention. When using six or more disks, a dedicated hot spare is highly recommended; size it to match the largest data disk in the pool, since smaller spares can&#8217;t protect every array member.<\/p>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section pcl-section--bordered\">\n  <div class=\"pcl-wrap pcl-wrap--narrow\">\n    <p class=\"pcl-eyebrow\">FAQ<\/p>\n    <h2 class=\"pcl-h2\">Frequently Asked Questions<\/h2>\n    <div class=\"pcl-faq-list\">\n      <div class=\"pcl-faq-item\"><h3>What is fault tolerance in RAID?<\/h3><p>It&#8217;s how many drives can fail before you lose data. RAID 5 survives one failure; RAID 6 survives two; RAID 10 survives one per mirror pair. RAID protects against drive failure, not operator error or non-disk disasters &mdash; always maintain a separate backup.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>Does RAID make my read\/write speed faster?<\/h3><p>Only RAID 0 and RAID 10 meaningfully improve speed via striping. All other RAID levels protect data but incur a write penalty, since multiple disks must write parity information.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>Will RAID work with an odd number of drives?<\/h3><p>Yes for RAID 5 (3+ drives) and RAID 0\/1. RAID 6 needs 4+, and RAID 10 needs even pairs of matching drives.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>How much usable storage will I get from RAID 5?<\/h3><p>Use (n &minus; 1) &times; drive size. Five 6TB drives in RAID 5 yields approximately 24TB usable.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>Which RAID level offers the best data protection?<\/h3><p>RAID 6 for traditional HDD arrays, since it survives two failures during a lengthy rebuild. RAID 5 is usually sufficient for SSD arrays, which rebuild in minutes rather than hours.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>What is the difference between RAID 0 and RAID 1?<\/h3><p>RAID 0 stripes data for maximum performance and capacity with zero redundancy. RAID 1 mirrors data, halving usable capacity but surviving the failure of either disk &mdash; opposite ends of the performance-vs-protection spectrum.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>How does JBOD work and when should I use it?<\/h3><p>JBOD connects drives individually or chains them into one volume with no parity or mirroring. Use it only when drives are backed up separately, such as for archival or cold storage.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>What is a hot spare in RAID?<\/h3><p>An unassigned standby disk attached to the controller. On any drive failure, the controller automatically assigns the hot spare and begins rebuilding &mdash; no user intervention required.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>What is a RAID storage calculator?<\/h3><p>A tool that computes your usable capacity based on disk count, individual drive capacity, and selected RAID level, accounting for parity, mirroring, or striping overhead &mdash; enter your inputs and it instantly returns usable capacity, fault tolerance limits, and redundancy details.<\/p><\/div>\n      <div class=\"pcl-faq-item\"><h3>What is the maximum bandwidth of PCIe 3.0?<\/h3><p>PCIe 3.0 delivers about 1GB\/s per lane &mdash; a standard x4 NVMe slot provides up to ~3.94GB\/s sequential throughput. PCIe 4.0 doubles that to ~8GB\/s per x4 slot. For RAID 10 NVMe arrays, lane count and generation are the primary ceiling on total array bandwidth.<\/p><\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is fault tolerance in RAID?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"It's how many drives can fail before you lose data. RAID 5 survives one failure; RAID 6 survives two; RAID 10 survives one per mirror pair. RAID protects against drive failure, not operator error or non-disk disasters \u2014 always maintain a separate backup.\"}},\n{\"@type\":\"Question\",\"name\":\"Does RAID make my read\/write speed faster?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Only RAID 0 and RAID 10 meaningfully improve speed via striping. All other RAID levels protect data but incur a write penalty, since multiple disks must write parity information.\"}},\n{\"@type\":\"Question\",\"name\":\"Will RAID work with an odd number of drives?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes for RAID 5 (3+ drives) and RAID 0\/1. RAID 6 needs 4+, and RAID 10 needs even pairs of matching drives.\"}},\n{\"@type\":\"Question\",\"name\":\"How much usable storage will I get from RAID 5?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Use (n \u2212 1) \u00d7 drive size. Five 6TB drives in RAID 5 yields approximately 24TB usable.\"}},\n{\"@type\":\"Question\",\"name\":\"Which RAID level offers the best data protection?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"RAID 6 for traditional HDD arrays, since it survives two failures during a lengthy rebuild. RAID 5 is usually sufficient for SSD arrays, which rebuild in minutes rather than hours.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the difference between RAID 0 and RAID 1?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"RAID 0 stripes data for maximum performance and capacity with zero redundancy. RAID 1 mirrors data, halving usable capacity but surviving the failure of either disk \u2014 opposite ends of the performance-vs-protection spectrum.\"}},\n{\"@type\":\"Question\",\"name\":\"How does JBOD work and when should I use it?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"JBOD connects drives individually or chains them into one volume with no parity or mirroring. Use it only when drives are backed up separately, such as for archival or cold storage.\"}},\n{\"@type\":\"Question\",\"name\":\"What is a hot spare in RAID?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"An unassigned standby disk attached to the controller. On any drive failure, the controller automatically assigns the hot spare and begins rebuilding \u2014 no user intervention required.\"}},\n{\"@type\":\"Question\",\"name\":\"What is a RAID storage calculator?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"A tool that computes your usable capacity based on disk count, individual drive capacity, and selected RAID level, accounting for parity, mirroring, or striping overhead \u2014 enter your inputs and it instantly returns usable capacity, fault tolerance limits, and redundancy details.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the maximum bandwidth of PCIe 3.0?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"PCIe 3.0 delivers about 1GB\/s per lane \u2014 a standard x4 NVMe slot provides up to ~3.94GB\/s sequential throughput. PCIe 4.0 doubles that to ~8GB\/s per x4 slot. For RAID 10 NVMe arrays, lane count and generation are the primary ceiling on total array bandwidth.\"}}\n]}\n<\/script>\n\n<section class=\"pcl-section\">\n  <div class=\"pcl-wrap\">\n    <p class=\"pcl-eyebrow\">Summary<\/p>\n    <h2 class=\"pcl-h2\">Which Configuration Is Right for You?<\/h2>\n    <div class=\"pcl-grid pcl-grid--summary\">\n      <div class=\"pcl-card\">\n        <span class=\"pcl-card-number\">01<\/span>\n        <h3>Home Users<\/h3>\n        <p>Want single-drive fault tolerance and efficiency? Use RAID 5 for your home NAS build.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <span class=\"pcl-card-number\">02<\/span>\n        <h3>Business-Critical Apps<\/h3>\n        <p>Need uptime despite slow HDD rebuild times? Use RAID 6 for business-critical applications.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <span class=\"pcl-card-number\">03<\/span>\n        <h3>High-Speed Performance<\/h3>\n        <p>Need high-speed read\/write with redundancy? Use RAID 10 for performance-critical applications.<\/p>\n      <\/div>\n      <div class=\"pcl-card\">\n        <span class=\"pcl-card-number\">04<\/span>\n        <h3>Data Backup Strategy<\/h3>\n        <p>RAID protects against drive failures, not ransomware or accidental deletion &mdash; always run a separate backup plan alongside it.<\/p>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<section class=\"pcl-section\" style=\"padding-top:0;\">\n  <div class=\"pcl-wrap pcl-bridge-grid\">\n    <a href=\"https:\/\/pccaselab.com\/nas-home-server\" class=\"pcl-bridge-card\">\n      <strong>Just getting started with NAS?<\/strong>\n      <span>See our NAS &amp; Home Server Guide &rarr;<\/span>\n    <\/a>\n    <a href=\"\/best-raid-for-nas\" class=\"pcl-bridge-card\">\n      <strong>Not sure which RAID level to pick?<\/strong>\n      <span>Read Best RAID for NAS &rarr;<\/span>\n    <\/a>\n  <\/div>\n<\/section>\n\n<\/div>\n\n","protected":false},"excerpt":{"rendered":"<p>Use our free RAID capacity calculator to instantly calculate usable storage, fault tolerance, and cost for RAID 0, 1, 5, 6, 10, 50, 60, and JBOD. Enter your drive count and size to get results in 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