AMCC PN 720-0104-00 manual Unit Write Cache, Unit Policies

3ware Disk Manager (3DM 2)

For additional information, see“Setting Background Task Rate” on page 113.

Unit Write Cache

You can enable or disable write cache for each unit.3DM lists each unit on the controller specified in the drop-down list on the menu bar, and shows you whether the write cache is currently enabled or disabled for it.

Write cache is a combination of the physical hard drives’ write cache as well as the controller’s memory, depending on what type of unit you are using.

For 9000-series controllers, a Disable Write Cache on Unit Degrade setting can be set in 3ware BIOS Manager (3BM). You can see if this setting is enabled in the Other Controller Settings field at the bottom of this Controller Settings page. If Disable Write Cache on Unit Degrade is enabled, upon degrade of a unit, the write cache will automatically be disabled, even if you enable write cache in the Unit Write Cache field.

For additional information, see “Enabling and Disabling the Unit Write Cache” on page 89.

Unit Policies

For units on 9000-series controllers, you can enable or disable two policies: Auto-verifyand Continue on Source Error During Rebuild. 3DM lists each unit on the controller specified in the drop-down list on the menu bar, and shows you whether the policies are currently enabled or disabled for each unit.

This section does not appear for 7000- and 8000- series controllers.

Auto-verify.The Auto-verify policy causes verify tasks to be performed repeatedly during a scheduled verify window. When Auto-verify is disabled, verify is not initiated automatically by the controller. Verify can still be started manually with 3DM, 3BM, or CLI. Once a manually-started verification is complete, no further verify tasks for the unit is performed.

Continue on Source Error During Rebuild. This policy applies only to units which are redundant. (For units which are not redundant, a check box is not available.) When this policy is set, ECC errors are ignored when they are encountered during a rebuild. When this policy is not set, a rebuild will abort upon encountering an ECC error and the unit will be set back to Degraded.

Since this option could result in the loss of some source data in the event of source errors, select this option only if you want to ensure that a rebuild will complete successfully without manually intervention. If the rebuild fails and Continue on Source Error During Rebuild is not selected, then you have the option to start a rebuild manually. It is recommended that a file system check be executed when the rebuild completes.

54 3ware 9000 Series Serial ATA RAID Controller User Guide