RAID levels

A RAID level is any of the possible configurations of a RAID disk array. RAID stands for redundant array of independent disks.
RAID levels may refer to:

Standard RAID levels, all the RAID configurations defined in the Common RAID Disk Drive Format standard, which is maintained by the Storage Networking Industry Association
Nested RAID levels, RAID configurations that incorporate features of two or more standard RAID levels
Non-standard RAID levels, variants of standard or nested RAID levels. Non-standard RAID levels deviate from the standard configurations defined by the Storage Networking Industry Association.