The controller transfers data from the logical drive to its local cache in increments equal to the stripe-unit size. This provides excellent overall performance when workloads are steady and sequential. However, if the workload is random or the system I/O requests are smaller than the stripe-unit size, reading ahead to the end of the stripe might degrade performance.
The controller transfers data from the logical drive to its local cache in increments equal to the system I/O request size, without reading ahead to the end of the stripe. This provides excellent overall performance when the workload is random or the system I/O requests are smaller than the stripe-unit size.
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