User guide

Current Write Policy
This item displays the status of the current write cache for this logical drive. The status varies
depending on the settings of the write cache for each logical drive, settings of the write cache
for the entire controller (Adaptive Writeback Cache), existence of battery connection and
battery status in an environment where a battery is connected. For the Adaptive Writeback
Cache, see “3.5.2 Controller.”
Setting of Adaptive
Writeback Cache
Battery status Write Policy (write
cache settings for
each logical drive)
Current Write Policy
Write Back Write Back No battery connected or
abnormal status
Write Through Write Through
Write Back Write Back
Disable
Battery connected and
normal status
Write Through Write Through
Write Back Write Through No battery connected or
abnormal status
Write Through Write Through
Write Back Write Back
Enable
Battery connected and
normal status
Write Through Write Through
Settings tab
Alias Alias name
Read Cache: Uses the cache when reading.
Read Ahead: Uses the cache when reading and provides read ahead. Improves
the performance by reading ahead before request.
Read Policy
No Cache: Does not use the cache when reading.
Write Through: Does not use cache when writing.
Write Back: Always uses cache when writing. This setting can improve write
performance.
Write Policy
However, despite the setting, the actual write cache status may vary depending
on the setting of write cache for the controller (Adaptive Writeback Cache) and on
the battery status. See the description of the Current Write Policy in the
Information tab in "3.5.9 Logical Drive" for details.
If you change either or both of the policies, click [Submit] to enable the change.
IMPORTANT: If you change an option for Read Policy,
it is effective immediately.
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