Introduction to RAID : RAID Levels : RAID 50

RAID 50

RAID 50 provides the features of both RAID 0 and RAID 5. RAID 50 includes both parity and disk striping across multiple drive groups. RAID 50 is best implemented on two RAID 5 drive groups with data striped across both drive groups.

RAID 50 breaks up data into smaller blocks and then stripes the blocks of data to each RAID 5 disk set. RAID 5 breaks up data into smaller blocks, calculates parity by performing an exclusive-or on the blocks and then writes the blocks of data and parity to each drive in the drive group. The size of each block is determined by the stripe size parameter, which is set during the creation of the RAID set.

RAID level 50 can support up to 8 spans and tolerate up to 8 drive failures, though less than total drive capacity is available. Though multiple drive failures can be tolerated, only one drive failure can be tolerated in each RAID 5 level drive group.

The following table provides an overview of RAID 50.

Table 12. RAID 50 Overview

Uses

Appropriate when used with data that requires high reliability, high request rates, high data transfer, and medium-to-large capacity.

Strong points

Provides high data throughput, data redundancy, and very good performance.

Weak points

Requires 2 times to 8 times as many parity drives as RAID 5.

Drives

8 spans of RAID 5 drive groups containing 3 to 32 drives each (limited by the maximum number of devices supported by the controller)

Figure 16. RAID 50 Level Virtual Drive