Wednesday, October 19, 2011

RAID 50 for database server!!! Good or Bad idea!


Just in case you wonder if RAID 50 is any good for database server!.

Dell says RAID 50 is great. Well It might be....... but not really for SQL database server. My and Microsoft view is that RAID 10 is a way to go because of excellent read and write performance.


RAID 50 is excellent for read but only “good” for random writes.


B.T.W , RAID 50 is a vendor specific configuration where multiple raid 5 arrays are striped across as well. It is still doing parity and now double the time. So how it can be good for write!!!..Not sure may be dell have done something else as well. In terms of performance it lies between RAID 10 and RAID 5.
 

According to equallogic , RAID Characteristics:
 

Table: RAID Level Characteristic Comparison
Workload Requirement
RAID10
RAID 50
RAID 5
RAID 6
Capacity
Average
Good
Excellent
Good
Availability
Excellent
Good
Average
Excellent
Sequential reads
Excellent
Excellent
Excellent
Excellent
Sequential writes
Good
Good
Good
Good
Random reads
Excellent
Excellent
Excellent
Excellent
Random writes
Excellent
Good
Average
Average
Performance impact of drive failure or RAID reconstruction
Minimal
Moderate
Moderate to heavy
Heavy



Random writes  are good in RAID 50 but excellent in RAID 10.