Dell PowerVault 221S (SCSI) User Manual
Page 13

A REFERENCE GUIDE FOR OPTIMIZING DELL™ SCSI SOLUTIONS
VER A02
PAGE 13
11/17/2005
Additional configuration factors
Hot Spares
Hot Spare functionality provides extra security availability and redundancy by replacing a
failed drive, allowing the rebuild of the degraded array to begin immediately. Both the
Adaptec and LSI based PERC controllers’ support this feature, but a simple SCSI
controller would not. See the controller user’s guide for details and limitations. Use of Hot
Spares is recommended whenever possible.
Clustering Considerations
In a cluster environment the cache being disabled on the controller poses a significant
performance impact to RAID 5 and RAID 50 configurations. If the system is to be clustered
RAID 10 is the optimal RAID level.
• Table
2-17: Cluster Solution Vs RAID Levels
RAID Level
Concatenated
0
1
10
5
50
Cluster
Solutions
Not Recommended
Recommended
Possible
Considerations for Optimal RAID Performance
The PowerVault™ 22xS is capable of offering increased performance by allowing multiple
channels to connect to the storage enclosure. This ability can increase the performance
of most configurations by allowing a multi channel RAID controller to increase the
bandwidth of the SCSI bus. For more information see Table 4-2: PV22xS Configuration
Topologies vs RAID Level Performance.
• Table
2-1
2-7: RAID Level Benefit (Generalized)
Clustering Multi Channel Relative Cost
Capacity
Scalability
Concatenated drives
None None None
Excellent
Excellent
RAID 0
None Excellent None Excellent
None
RAID 1
Moderate Excellent Excellent None
None
RAID 10
Excellent Excellent Excellent None
Excellent
RAID 5
Moderate Moderate Moderate
Moderate
Moderate
RAID 50
Moderate Moderate Moderate
Moderate
Moderate