RAID-5
RAID-5 is shorthand for RAID Level 5: Independent data disks with distributed parity blocks.
RAID Level 5 is a type of RAID configuration which uses 3 or more disks to provide redundancy in case of a drive failure, combined with striping to increase read/write speed.
Parity bits are scattered over all disks.
Features:
- Availability: Can tolerate the loss of 1 drive
- Capacity: 66% or higher (3 drives = 2 drive available space, 4 drives = 3 drive available space)
- Degradation: Performance decreases substantially until the failed drive is replaced and rebuilt
- Performance: Highest read speed (up to 3x single disk), medium write speed
- Summary: Combination of good performance, good fault tolerance, high storage efficiency
- Typical Uses: File and application servers, databases, web, email servers, intranet servers
How it works
- READ: read data blocks from 3 or more disks at the same time
- WRITE: read parity block, write data block, write parity block
Comparison with other RAID types:
- RAID-0 has faster writes and equal read speed (for a 3-drive RAID-0 set)
- RAID-1 has faster writes and slower reads
