Changing The Write Policy - Hitachi 220H Bios Manual

Changing the write policy

This section describes a procedure of changing the write policy of a virtual drive.
You can expect better write performance if you enable the write cache of the
virtual drive.
NOTICE
1. Click Virtual Drives in the main menu.
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You need connect the AC cables of the system unit to a UPS, when you
use the RAID controller without cache backup module and set Write
Policy to Always Write Back. Otherwise, the data corruption may
result when blackout or momentary loss of power occurs.
If you use the RAID controller without cache backup module, use

Write Through setting when installing an OS. Even if the system
unit is connected to a UPS, the install may not finish normally.
If you use the RAID controller with cache backup module, use only

Write Back With BBU setting. Otherwise, write performance may
be compromised.
If multiple virtual drives reside on the same Drive Group, keep the

same setting for all the virtual drives.
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Hitachi Compute Rack 210H/220H BIOS Guide