Enabling And Disabling The Unit Write Cache - 3Ware 9550SXU-12 User Manual

Configuring Units

Enabling and Disabling the Unit Write Cache

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Figure 55. Unit Policies on Controller Settings Page in 3DM
Write cache is used to store data locally in memory on the controller before it
is written to the disk drive media, allowing the computer to continue with its
next task. This improves performance. However, there may be instances when
you want the computer to wait for the drive to write all the data to disk before
going on to its next task. In this case, you must disable the write cache.
Note:
If write cache is enabled, in the event of a power failure, the data in the
controller cache will be lost if you do not have a Battery Backup Unit (BBU). To
avoid a sudden power failure if you do not have a BBU, it is advisable to have an
Uninterruptible Power Supply (UPS).
Write cache can be turned on or off for individual units in 3DM, CLI, and
3BM without changing the configuration or losing data from the drives.
3ware SAS/SATA RAID Software User Guide, Version 9.5.1