Changing An Existing Configuration by Migratingwww.3ware.com 121RAID Level Migration (RLM) OverviewRAID level migration is the process of converting one RAID configuration toanother. When you migrate a unit to a different configuration, the user data onit is redistributed to the format of the new configuration. This dataredistribution process is a background task, similar to the rebuild or verifyprocesses.Figure 57 shows an example of how data is reconfigured during a migration.In this example, the migration is from a 3-drive RAID 0 to a 4-drive RAID 5,with both having the same stripe size. As can be seen, every piece of user datais moved from its original physical location.Figure 57. RAID Level Migration ExampleTypically, a unit is reconfigured with the same or more storage capacity.Sometimes additional drives are added. The following table shows validreconfigurations, some of which will require the addition of more drives.Table 10: Valid Migration PathsDestinationSource R0 R1 R5 R6 R10 R50 Single JBOD SpareR0 Yes No Yes Yes Yes Yes No No NoR1 Yes No Yes Yes Yes Yes Yes No NoR5 Yes No Yes Yes Yes Yes No No NoR6 Yes No Yes Yes Yes Yes No No NoR10 Yes No Yes Yes Yes Yes No No NoR50 Yes No Yes Yes Yes Yes No No No
