RAID-Level, Anzahl & Größe der Festplatten — nutzbare Kapazität sofort sehen.
| RAID-Level | — |
|---|---|
| Beschreibung | — |
| Festplatten | — |
| Gesamtkapazität (raw) | — |
| Nutzbare Kapazität | — |
| Overhead | — |
| Effizienz | — |
| Ausfallsicherheit | — |
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RAID 0 (Striping) distributes data across all disks — maximum capacity and speed, but no redundancy. One disk failure destroys all data.
RAID 1 (Mirroring) mirrors data 1:1 — half the capacity, but full redundancy. Ideal for operating system disks.
RAID 5 requires at least 3 disks and uses distributed parity. One disk may fail. Good compromise between capacity and safety.
RAID 50 & 60 (Nested RAID) combine striping with parity groups. RAID 50 (RAID 0 over RAID 5) tolerates one disk failure per group, RAID 60 (RAID 0 over RAID 6) tolerates two per group — ideal for large storage arrays with high performance.
A hardware RAID controller (e.g. LSI/Broadcom, Adaptec) calculates parity on a dedicated chip — expensive, but OS-independent. Software RAID (mdadm on Linux, Storage Spaces on Windows, ZFS) uses the host CPU. Modern CPUs make software RAID practically as fast as hardware RAID for RAID 0/1/10, but hardware RAID remains faster for RAID 5/6 with parity calculations. Our calculator provides the correct capacity values for both variants.
A typical situation: you are ordering a new server and want to install 4 × 2 TB disks — but RAID 5 or RAID 10? Or a colleague looks at your 6-disk array and asks why 24 TB only yields 20 TB of usable capacity. That is exactly what this calculator is for: pick the RAID level, enter disks and size, read off the usable capacity — including overhead and efficiency.
Choose the RAID level: 0, 1, 5, 6, 10, 50, or 60.
Enter the number of disks and their size in GB.
Read off usable capacity, overhead, and fault tolerance immediately — no spreadsheet, no calculator needed.
Up to four disks and one failure to survive: RAID 5 — the best balance of capacity and safety. Once disks get large (8 TB and up), rebuilds take a long time; then RAID 6 is the safer choice, because a rebuild runs the array at full load and a second failure would be fatal. If performance comes first or the disks are mirrored anyway: RAID 10.
Redundancy costs capacity: RAID 5 sacrifices exactly one disk (parity), RAID 6 two disks (double parity), RAID 10 half of the array (mirror). With 4 × 2 TB that means: RAID 5 → 6 TB usable, RAID 6 → 4 TB, RAID 10 → 4 TB. The calculator shows you this at a glance before you buy the disks.
Three: two disks carry the data, one carries the parity. With three disks, RAID 5 survives exactly one failure. More disks increase usable capacity, not fault tolerance.
Only as a temporary speed solution, e.g. render cache or game storage. RAID 0 has no redundancy — one failed disk destroys the data on all disks of the array. Without a backup, that is a lottery ticket.
A spare disk that sits in the enclosure and automatically takes over when a disk fails. The rebuild starts without manual intervention — practical for servers that run around the clock. At home you usually do not need it.
After a disk failure, the data is rebuilt from the remaining disks plus parity onto the replacement disk. With large disks this takes hours to days — during that time the array runs in degraded mode, and a second failure would be critical.
The official specification comes from SNIA (Storage Networking Industry Association). Calculate IOPS and performance for your array with the IOPS Calculator. Hands-on knowledge: RAID Levels in Practice and Understanding Disk Performance.
🔐 RAID planned? Generate secure passwords for your server access.