Understanding enabled and disabled read-ahead cache mode for logical drives

  You can enable and disable the read-ahead setting without destroying data in a logical drive by using the ServeRAID Manager in bootable-CD mode.

Enabled read-ahead cache mode

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.

Disabled read-ahead cache mode

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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