## Changing the write-cache m ode on a logical drive

(Startable-CD mode only.)

Use this action to change the write-cache mode setting of a logical drive to write through or write back.

1. Click a logical drive from the Main Tree.
2. Click Actions --> Change write-cache mode to write back/write through.
3. If you click write back and you do not have a battery-backup cache, click Yes to confirm your choice because there is a risk of losing data.
   If you click write back and you do have a battery-backup cache, the ServeRAID Manager changes the mode.
   If you click write through, the ServeRAID Manager changes the mode.

The write-cache mode determines if the controller writes data to the hard disk drive before or after sending a confirmation to the operating system.

Notes: | If you configure RAID level-x0 logical drives, all logical drives in the spanned array must be either write back or write through. That is, the write-cache mode settings for the logical drives in the spanned array cannot be a mixture of write back and write through. If you configure a fault-tolerant pair of controllers, the controllers must be configured as write through. If you have the battery-backup option, it is disabled when you create a fault-tolerant pair. The write-cache mode is changed automatically from write-back mode to write-through mode. For more information, refer to the IBM ServeRAID-4 Ultra160 SCSI Controller User's Reference.

### See also

Understanding write-back and write-through modes