NEC Express5800 series User Manual page 92

4-48
Configuring Your Storage and I/O Blade
The Disk Cache Policy has the following modes. Select a mode suitable for your environment.
Unchanged
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Enabled
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Disabled
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IMPORTANT:
If "Unchanged" is specified for Disk Cache Policy, the default value
may not be identical to the factory-set value, therefore, do not
specify this mode.
If Enabled is specified for Disk Cache Policy, the controller uses the
write cache policy of the hard disk drive. Accordingly, the data in
cache memory of the hard disk drive may be lost at an occurrence of
power failure.
Be sure to use UPS when using the cache memory of the hard disk
drive.
You can change parameters for VD definition except for RAID Level and Stripe Size. On the
WebBIOS Top Menu, click [Virtual Drives] and specify parameters in "Policies" frame, then click
[Change].
The controller uses the default write cache policy of hard disk drive.
The default value may not be identical to the factory-set value, therefore, do not
specify this mode.
The controller always uses the write cache policy of hard disk drive.
Be sure to use UPS when specifying this mode for disk cache policy.
The controller does not use the write cache policy of the hard disk drive.
This mode can provide the highest data security, however, the writing
performance is lower than that in Enabled mode.
It is recommended to use this mode for the sake of data security.