Dell PowerEdge R510 - Manual (Page 8)

Dell R510 Reference Configuration for Microsoft SQL Server® 2008 R2 Fast Track Data Warehouse
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Figure 2. Virtual Disk Settings
Stripe element size
By default, the PERC H700 creates virtual disks with a segment size of 64KB. During the Fast Track
validation testing we utilized stripe element sizes of 64KB and 1MB to compare and contrast any
performance improvements. For most workloads, 64KB default size will provide an adequate stripe
element size. We recommend testing various sizes depending on the workload characteristics of your
configuration.
Read policy
The default setting for read policy on the PERC H700 is “adaptive read ahead”. During testing,
however, we observed that changing the setting to “No read ahead” improved the overall performance
by 4%; we attribute the improvement to unnecessary read ahead during large sequential I/O requests.
Adaptive read ahead typically improves performance in small random workloads.