Dell Understanding Disk Cache Policy: Write-Back vs Write-Through and H310 vs H710

4Exit the BIOS Configuration Utility and reboot the system.

5Ensure that all the latest drivers for the PERC H710, H710P, or H810 card (available at support.dell.com) are installed.

For more information, see "Driver Installation" on page 43.

Virtual Disk Write Cache Policies

NOTE: PERC H310 only supports Write-Throughmode.

The write cache policy of a virtual disk determines how the controller handles writes to the virtual disk. Write-Backand Write-Throughare the two write cache policies and can be set on virtual disks individually.

All RAID volumes are presented as Write-Throughto the operating system (Windows and Linux) independent of the actual write cache policy of the virtual disk (except PERC H310, which only supports Write-Back). The PERC cards manage the data in cache independently of the operating system or any applications.

NOTE: Use the Dell OpenManage storage management application or the BIOS Configuration Utility to view and manage virtual disk cache settings.

Write-Back and Write-Through

In Write-Throughcaching, the controller sends a data transfer completion signal to the host system when the disk subsystem has received all the data in a transaction.

In Write-Backcaching, the controller sends a data transfer completion signal to the host when the controller cache has received all the data in a transaction. The controller then writes the cached data to the storage device in the background.

The risk of using Write-Backcache is that the cached data can be lost if there is a power failure before it is written to the storage device. This risk is mitigated by using a Non-Volatile Cache on the PERC H710, H710P or H810 card.

NOTE: The default cache setting for virtual disks is Write-Backcaching.

NOTE: Certain data patterns and configurations perform better with a Write-Throughcache policy.

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