Hitachi 220H Bios Manual page 108

11. The following window is displayed.
While all the displayed virtual drives are selected, specify the RAID level, strip
size, read policy, write policy, and virtual drive size as shown in the table
below:
Set each item in the following value to the recommended value, unless
otherwise specified.
NOTICE
2-44
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.
MegaRAID WebBIOS
Hitachi Compute Rack 210H/220H BIOS Guide