Raid Level Migration (Rlm) Overview - 3Ware 9650SE-2LPML User Manual

Chapter 8. Configuring Units

RAID Level Migration (RLM) Overview

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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 54 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 54. 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
Source R0 R1
Yes No
R0
Yes No
R1
Yes No
R5
Yes No
R6
Yes No
R10
Yes No
R50
Destination
R5 R6 R10 R50
Yes Yes Yes Yes
Yes Yes Yes Yes
Yes Yes Yes Yes
Yes Yes Yes Yes
Yes Yes Yes Yes
Yes Yes Yes Yes
3ware Serial ATA RAID Controller User Guide
Single JBOD Spare
No No No
Yes No No
No No No
No No No
No No No
No No No