RAID

Redundant Array of Independent/Inexpensive Disks (RAID)

It is a technology that combines multiple physical disk drives into one or more logical units for data redundancy, performance improvement or both.

Types

Standard Levels

• RAID 0
• RAID 1
• RAID 2
• RAID 3
• RAID 4
• RAID 5
• RAID 6

Nested (Hybrid) RAID

• RAID 0+1
• RAID 1+0
• JBOD RAID N+N (JBOD = Just a bunch of disks)

Non-standard Levels (mostly proprietary)

• Linux MD RAID 10
• Hadoop RAID
• BeeGFS
• Declustered RAID

Software RAID

Virtual Device

• Linux's md
• OpenBSD's softraid

Logical Volume Manager

• Veritas
• LVM

A component of the Filesystem

• ZFS - RAID 0 | RAID 5 (RAID-Z1) single parity | RAID 6 (RAID-Z2) double parity and triple parity (RAID-Z3/RAID 7)
• Spectrum Scale
• Btrfs
• XFS

OS implementations

• HP OpenVMS - RAID 1
• macOS - RAID 0 | RAID 1 | RAID 1+0
• FreeBSD - RAID 0 | RAID 1 | RAID 3 | RAID 5 | All nestings
• Linux - RAID 0 | RAID 1 | RAID 4 | RAID 5 | RAID 6 | All nestings
• Windows - RIAD 0 | RAID 1 | RAID 5
• NetBSD - RAID 0 | RAID 1 | RAID 4 | RAID 5
• OpenBSD - RAID 0 | RAID 1 | RAID 5