Raid 50 Arrays - Adaptec CDP-00277-01-A Installation And User Manual

RAID 50 Arrays

A RAID 50 array is built from six to forty-eight disk drives configured 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 Arrays on page 67.)
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 figure, P represents the distributed parity data.
Each RAID 5 Logical Drive has
RAID 5
A
1, 5, P 3, P, 9
Drive 1 Drive 2
250 GB 250 GB
Proprietary and Confidential to PMC-Sierra, Inc.
Document No.: CDP-00277-01-A Rev. A, Issue:
Serial Attached SCSI RAID Controllers Installation and User's Guide
RAID 50
Logical Drive
=
1000 GB
plus Parity
500 GB Data Storage
250 GB Parity Data
P, 7, 11 2, 6, P
Drive 3
250 GB
Drive 4
400 GB
RAID 5
B
4, P, 10 P, 8, 12
Total Unused
Space = 150 GB
Drive 5 Drive 6
400 GB 400 GB
68