Dell Shared PowerEdge RAID Controller (PERC) 8 For Dell PowerEdge VRTX Systems User’s Guide

Write-back caching is the default caching mode for single and dual Shared PERC 8 card configurations. Write-back caching can be configured under all conditions in which the battery is present and in good condition.

If a virtual disk is already created on the VRTX system with the firmware version that does not support write-back caching, then the default will remain as write-through. The virtual disk must be manually changed to write-back before it goes to write-back mode, even if the system has been updated to a write-back supported firmware version.