Creating arrays
6 Select Manual Configuration, then press ENTER. The Select Chunk Size screen opens.
The available chunk sizes are 64 K, 128 K, and 256 K. This is the amount of data that is written on a single drive before the controller moves to the next drive in the stripe.
To achieve optimum RAID 5 write performance you should consider setting the chunk size based on the specified number of drives for a Full Stripe Write when configuring RAID 5/50 arrays. See “Optimizing RAID 5 Write Performance” on page 227 for detailed information.
The primary aim of setting a chunk size is to try to set a stripe size that allows for full stripe writes. The stripe size is determined by the number of data drives multiplied times the chunk size, (8 data drives × 64 K chunk size = 512 strip size).
For maximum performance with RAID 5/50 arrays, you want to do as many full stripe writes as possible. Typically, Windows NT, Windows 2000, and Windows 2003 access at 64 K. Therefore, a stripe size of up to 1 MB would mean the controller has to cluster 16 commands to perform a full stripe write (actually 17 because of alignment). If you were to use a larger stripe size, you run the risk of not being able to cluster sufficiently for the application.
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