Changing An Existing Configuration by Migrating
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RAID Level Migration (RLM) Overview
RAID level migration is the process of converting one RAID configuration to
another. When you migrate a unit to a different configuration, the user data on
it is redistributed to the format of the new configuration. This data
redistribution process is a background task, similar to the rebuild or verify
processes.
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 data
is moved from its original physical location.
Figure 57. RAID Level Migration Example
Typically, a unit is reconfigured with the same or more storage capacity.
Sometimes additional drives are added. The following table shows valid
reconfigurations, some of which will require the addition of more drives.
Table 10: Valid Migration Paths
Destination
Source
R0
R1
R5 R6
R10
R50
Single
JBOD
Spare
R0
Yes
No
Yes
Yes
Yes
Yes
No
No
No
R1
Yes
No
Yes
Yes
Yes
Yes
Yes
No
No
R5
Yes
No
Yes
Yes
Yes
Yes
No
No
No
R6
Yes
No
Yes
Yes
Yes
Yes
No
No
No
R10
Yes
No
Yes
Yes
Yes
Yes
No
No
No
R50
Yes
No
Yes
Yes
Yes
Yes
No
No
No
