Microsemi Adaptec ASR-8405E - RAID 50 Arrays

B.8 RAID 50 Arrays
A RAID 50 array is built from six to forty-eight disk drives congured as two or more RAID 5 arrays, and
stripes stored data and parity data across all disk drives in both RAID 5 arrays. (For more information, see
RAID 5 ArraysRAID RAID 5arrays RAID 5.)
The parity data provides data protection, and striping improves performance. RAID 50 arrays also provide
high data transfer speeds.
Drive segment size is limited to the size of the smallest disk drive in the array. For example, three 250 GB
disk drives and three 400 GB disk drives comprise two equal-sized RAID 5 arrays with 500 GB of stored data
and 250 GB of parity data. The RAID 50 array can therefore contain 1000 GB (2 x 500 GB) of stored data
and 500 GB of parity data.
In this gure, P represents the distributed parity data.
RAID 5
B
RAID 50
Logical Drive
=
1000 GB
plus Parity
RAID 5
A
Each RAID 5 Logical Drive has
500 GB Data Storage
250 GB Parity Data
Drive 1
250 GB
Drive 2
250 GB
Drive 3
250 GB
Drive 4
400 GB
Drive 5
400 GB
Drive 6
400 GB
Total Unused
Space = 150 GB
2, 6, P 4, P, 10 P, 8, 121, 5, P 3, P, 9 P, 7, 11
54
Microsemi Proprietary and Condential. Installation and User's Guide Revision 5
Understanding RAID