Lots of resources.
RAID Levels
RAID levels indicate how the RAID (redundent array of independent/inexpensive drives) is working together. Some of the most commonly used RAID levels are: RAID level 0, RAID level 1, RAID level 3, RAID level 5 and RAID level 0 1 (or 0+1).
RAID Level 0 - Striping
RAID Level 1 - Mirroring
RAID Level 3 - Parity on a single drive
RAID Level 5 - Parity spread across all drives
RAID level 0 1 (0+1) - striping and mirroring
go to Internet (Google) and type "RAID Levels"
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