Chapter 4: Getting Started ● 30Choosing a RAID LevelThis section provides a brief overview of the RAID levels supported byyour Adaptec RAID controller, including the minimum and maximumnumber of disk drives required by each.Note: RAID 1E, RAID 5EE, RAID 6 and RAID 60 are available in theupgrade package. (See page 20.) For more information about RAIDlevels, see Understanding RAID on page 79.● RAID 0 (Non-redundant Array)—Stripes data across multiple diskdrives. Improved performance but no redundancy (see page 80).● RAID 1 Array—Created from two disk drives where one disk driveis a mirror of the other (the same data is stored on each disk drive).Redundancy, but reduced capacity (see page 81).● RAID 1E Array—Similar to a RAID 1 array except that data is mirroredand striped, and more disk drives can be included (see page 82).● RAID 5 Array—Stripes data for improved performance and usesparity data to provide redundancy (see page 84).● RAID 5EE Array—Similar to a RAID 5 array, but includes a distributedspare and must include a minimum of four disk drives (see page 85).● RAID 10 Array—Built from two or more equal-sized RAID 1 arrays,stripes and mirrors data across multiple disk drives. Redundancyand improved performance (see page 83).● RAID 501 Array—Built from multiple disk drives configured as twoor more RAID 5 arrays, stripes stored data and parity data across alldisk drives (see page 86).● RAID 6 Array—Similar to a RAID 5 array except that it includes twoindependent sets of parity data instead of one (see page 87).● RAID 60* Array—Similar to a RAID 50 array except that it includesfour independent sets of parity data instead of two (see page 88).Use the table on page 89 to see how many disk drives you must connectto your RAID controller to support the RAID level you want.1 Because it supports four disk drives only, the Adaptec 2420SA RAID controller can’tsupport RAID 50 or RAID 60.
