RAID Info RAID Level 0RAID Level 0 is not redundant, but allows multiple drives to act as one. In RAID-0, data is split across drives, resulting in higher data throughput. Since no redundant information is stored, while performance is very good, the failure of any disk will result in total data loss.
Two to six drives can be used, depending on the server. Usable Space = The sum of all drives in the array. RAID Level 1RAID Level 1 is also known as drive mirroring. It provides redundancy by duplicating all data from one drive to a second drive. The performance of a Level 1 array is only slightly better than a single drive, but if either drive fails, no data is lost.
Two drives of the same size are required. Usable Space = The size of one of the drives in the array. RAID Level 5RAID Level 5 stripes data across several drives, with parity data stored across all drives. The parity information allows recovery from the failure of any single drive. The performance of a level 5 array is very good for reads (the same as RAID-0). Writes require that parity data be updated which slows small random writes, although large or sequential writes are fairly fast.
Three or more drives are required. Usable Space = The sum of all drives in the array, less one drive. RAID 0+1RAID 0+1 is a multi-level array that stripes (RAID-0) data to separate mirrored (RAID-1) drive sets. RAID 0+1 offers higher performance than RAID-5, with redundancy, at the expense of usable space. As each drive in the array is mirrored, parity data does not need to be generated.
RAID 0+1 requires four SATA or SCSI drives. Usable Space = Half the sum of all drives in the array. |