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Enabling and Disabling the Unit Write Cache
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Enabling and Disabling the Unit Write
Cache
Write cache is used to store data locally on the drive before it is written to the
disk, allowing the computer to continue with its next task. Enabling write
cache results in the most efficient access times for your computer system.
However, there may be instances when you always 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.
Write cache can be turned on or off for individual units in both 3DM and 3BM
without changing the configuration or losing data from the drives.
If you have a BBU (Battery Backup Unit) installed on the controller, the
battery preserves the contents of the controller cache memory for a limited
period of time (up to 72 hours) in the event of a system power loss. When a
BBU is installed, if the battery is not “Ready,” write cache is disabled.
Notes:
For 9000-series controllers, a setting at the BIOS level in 3BM can
specify that the cache should be disabled in the event the unit
degrades. When that option is selected, unit write cache cannot be
enabled until the array is rebuilt and again in optimal mode. In
3DM, you can see whether
Disable write cache on unit degrade
is set in the
Other Controller Settings
section of the
Controller
Settings page
. For more information, see “Disabling Write Cache
on Unit Degrade” on page 79.
Write cache settings are not applicable for an unconfigured disk
(JBOD).
Note:
Do not use Windows Control Panel to enable or disable
cache on 3ware RAID units.
Enabling and Disabling the Unit Write Cache through
3DM
1
Choose
Management > Controller Settings
from the menu bar.
2
In the
Unit Write Cache
section of the Controller Settings Page, select
the Enabled or Disabled option for each unit.
Summary of Contents for 3ware 9000 Series
Page 1: ...3ware Serial ATA RAID Controller Supports the 9000 Series PN 720 0114 01 March 2005 User Guide...
Page 10: ...About This Guide 4 3ware 9000 Series Serial ATA RAID Controller User Guide...
Page 88: ...Configuring Your Controller 82 3ware 9000 Series Serial ATA RAID Controller User Guide...
Page 144: ...Maintaining Units 138 3ware 9000 Series Serial ATA RAID Controller User Guide...
Page 190: ...Glossary 184 3ware 9000 Series Serial ATA RAID Controller User Guide...
Page 202: ...196 3ware 9000 Series Serial ATA RAID Controller User Guide...