www.cryer.co.uk
Brian Cryer's Web Resources

RAID Level

RAID Level
RAID level is a number indicating the type of organisation of disks in the RAID array:
RAID 0 Striping. No redundancy. Fastest. Provides maximum storage. No fault tolerance.
RAID 1 Disk mirroring. Good performance. Fault tolerant. Only fault tolerant option if using 2 drives.
RAID 2 Error correction data written to separate disk.  
RAID 3 Striping (small stripe size) with one parity disk.  
RAID 4 Striping (large stripe size) with one parity disk.  
RAID 5 Striping with parity. Parity information is distributed across all drives. Good performance. Fault tolerant. Slowest to rebuild (if one disk is replaced). Better storage than RAID 1. Requires at least 3 disks. Tolerant of a single disk failure.
RAID 6 RAID 5 with an extra parity disk. Tolerant of two disks failing.
RAID 0+1 Mirrored array (RAID 1) whose segments are RAID 0 arrays, i.e. mirroring of striped sets.  
RAID 10 Striped array (RAID 0) of mirrored sets (RAID 1).  
RAID 53 Combination of RAID 0 and RAID 3. Each stripped set (of RAID 0) are RAID 3 sets.  

RAID 1 (disk mirroring) and RAID 5 (striping with parity) are the most common forms of RAID.

For more information see:

© Copyright 2004-2012, A B Cryer, All rights reserved.