RAID 5 Parity Rotation

In a RAID 5, parity data is generated to protect data against the failure of one disk. The parity data is distributed evenly among all component disks in a rotating pattern.

Forward

This rotation is used on software RAID created on a Windows® NT computer. This rotation is also observed on older controllers.

Warning: This statement is a general guideline. The RAID 5 parity rotation used by a particular manufacturer is subject to change without notice.

Backward

This rotation is used by the Dell MegaRAID® and the HP (formerly Compaq) controllers as well as most newer controllers.

Backward, symmetric

This rotation is used on software RAID 5 created on Windows® 2000, 2003, XP and Vista and a few RAID controllers. This rotation pattern balances the I/O load equally on all component disks.