IBM PC Server 520, Руководство пользователя

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Additional Disk-Array Tasks
Restoring the Disk-Array Configuration
To restore the disk-array configuration information in the
ServeRAID adapter, use the ServeRAID Adapter Configuration
Diskette and an up-to-date Disk Array Configuration Backup
diskette.
Note: Because dynamic changes in the configuration of your disk
array occur due to hot-spare drive replacement or other drive
maintenance activity, the configuration backup information
on the diskette might be different from that in the adapter. It
is important that you back up the disk-array configuration
information frequently, to keep the backup information on
the diskette current.
To restore the ServeRAID configuration information:
1. Start the ServeRAID configuration program (see “Starting the
ServeRAID Configuration Program” on page 80).
2. Select Advanced Functions from the Main Menu.
3. Select Restore config. from diskette.
4. Follow the instructions on the screen.
Changing the Write Policy
When you configure a logical drive, the RAID adapter automatically
sets the write policy to write-through (WT) mode, where the
completion status is sent after the data is written to the hard disk
drive. Under certain workloads, you can improve performance by
changing this write policy to write-back (WB) mode, where the
completion status is sent after the data is copied to adapter cache
memory, but before the data is actually written to the hard disk
drive.
Although you gain performance with write-back mode, it creates a
greater risk of losing data due to a power failure. This is because
the system gets a completion status message when the data reaches
adapter cache memory, but before data is actually written to the hard
disk drive.
Chapter 3. Configuring the Disk Array
117