Dell H710P, H310 Virtual Disk Read Cache Policies, Conditions Under Which Write-Back is Employed

Conditions Under Which Write-Back is Employed

Write-Backcaching is used under all conditions in which the battery is present and in good condition.

Conditions Under Which Forced Write-Back With No Battery is Employed

CAUTION: It is recommended that you use a power backup system when forcing Write-Back to ensure there is no loss of data if the system suddenly loses power.

Write-Backmode is available when you select Force WB with no battery. When Forced Write-Backmode is selected, the virtual disk is in Write-Backmode even if the battery is not present.

Virtual Disk Read Cache Policies

The read policy of a virtual disk determines how the controller handles reads to that virtual disk. The read policies are:

•Always Read Ahead—Allows the controller to read sequentially ahead of requested data and to store the additional data in cache memory, anticipating that the data is required soon. This speeds up reads for sequential data, but there is little improvement when accessing random data.

•No Read Ahead—Disables the Read-Aheadcapability.

•Adaptive Read Ahead—Begins using Read-Aheadif the two most recent disk accesses occurred in sequential sectors. If the read requests are random, the controller reverts to No Read Ahead mode.

NOTE: The default read cache setting for virtual disks is Adaptive Read Ahead.

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