# Understanding logical-drive migration

Logical-drive migration is a powerful and flexible feature of ServeRAID controllers. You can use logical-drive migration to:

- Change the RAID level of existing logical drives
- Increase array free space, so you can create additional logical drives
- Increase the size of an existing logical drive

You can migrate a logical drive while the server is running with only minor performance degradation for users during the process. You can start the migration immediately or schedule it for a later date and time.

HostRAID controllers do not support logical drive migration.

Notes: To perform a logical-drive migration, the following must be true:

- For ServeRAID SCSI controllers, no more than seven logical drives currently exist.

  During logical-drive migration, the ServeRAID Manager creates one logical drive for temporary use. (You must have an extra logical drive onto which the data can migrate.) The ServeRAID Manager sets this logical drive to the system state. When migration is complete, this logical drive is removed.

- The logical drive that you have selected to migrate must be in the okay state.
- For ServeRAID SCSI controllers, the logical drive cannot be configured with RAID level-00, 10, 1E0, 50, or 5EE.

If a physical drive fails during a logical-drive migration and you are migrating between RAID levels other than RAID level-0, the migration will continue and complete. Then, you must replace and rebuild the failed physical drive.

Logical-drive migrations also can recover from a power failure. If power is lost to the server during a logical-drive migration, the migration will restart as soon as power is restored, and complete without data corruption.

Note: (Cluster and failover configurations only) A logical drive will not failover while undergoing logical-drive migration.

## More information

- Things to consider when changing the RAID level
- Example: Increasing free space
- Example: Increasing logical drive size
- Understanding scheduled tasks
- Using the Task Manager

Glossary | Contents

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