RAID 50 and 60 split the disks into equal groups, each a RAID 5 or RAID 6 array.
Result
Every level with these disks
Speeds are theoretical multiples of one disk, for comparing levels. Controllers, caches and SSDs change real numbers a lot.
Choosing a RAID level
- RAID 0 stripes data over all disks: full capacity and speed, no protection. Use it only for scratch data you can lose.
- RAID 1 mirrors disks: simple and robust, with the capacity of one disk. Common for boot drives.
- RAID 5 gives up one disk’s capacity for parity and survives one failure. With today’s large disks a rebuild can take a day or more, and a second failure or an unreadable sector during it loses the array, so it is best kept to small, fast disks.
- RAID 6 keeps two disks of parity and survives any two failures: the usual choice for large hard drives in a NAS or file server.
- RAID 10 stripes across mirrored pairs. It costs half the capacity but has the best write performance and the quickest rebuilds, which suits databases and virtual machines.
- RAID 50 and 60 stripe across several RAID 5 or RAID 6 groups, for large arrays that need more speed and shorter rebuilds than one big group gives.
How capacity is calculated
The calculator assumes identical disks. If sizes differ, most controllers treat every disk as the size of the smallest, so use that. Drives are sold in decimal terabytes, while operating systems usually report binary tebibytes, which is why each figure is shown both ways: an 8 TB drive appears as about 7.28 TiB. File systems then take a few percent more for their own structures.
RAID is not a backup
RAID keeps a server running when a disk fails. It does not protect against deleted files, ransomware, a failed controller, fire or theft: those changes are copied to every disk at once. Keep separate backups, ideally one off-site. The calculations here run entirely in your browser.