A RAID-5 or striping with parity volume is used to combine unallocated space on three or more physical disks. To create a RAID-5 volume, you require minimum three physical disks. As with striped volumes, unallocated space on up to 32 physical disks can be combined to create a single striped volume, the amount of space allocated to the volume on each disk must be identical, and data is written to all the physical disks in the volume at the same rate (via striping). Unlike striping alone, RAID-5 writes the data with checksum information, called parity, which provides fault tolerance.
If one of the drives in a RAID-5 set fails, data on the failed disk can be regenerated using the parity information. The failed drive must be replaced or another drive must be specified as part of the volume to restore fault tolerance. System volumes cannot use RAID-5. If two disks in a RAID-5 set fail simultaneously, all data is lost and must be restored from backup