3Ware 9550SXU-16ML User Guide - Page 154

Chapter 8. Configuring Units Changing An Existing Configuration With 3ware 9000 series RAID controllers you can convert one RAID configuration into another while the unit is online. This process is known as RAID Level Migration (RLM). Note: Units on a 7xxx/8xxx series controller cannot be migrated. You can use RAID Level Migration to make two main types of configuration changes: „ RAID Level „ Unit Capacity Expansion You can also use RLM to change the stripe size of a unit. These changes can be made using 3DM2 or the CLI. Instructions for using migrate in 3DM2 are described below. For information about CLI, see 3ware 9000 Series Serial ATA RAID Controller CLI Guide. This section includes the following topics about changing existing configurations: „ RAID Level Migration (RLM) Overview „ Changing RAID Level „ Expanding Unit Capacity „ Informing the Operating System of Changed Configuration 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 63 shows an example of how data is reconfigured during a migration. In this example, the migration is from a 4-drive RAID 0 to a 6-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. 144 3ware 9550SX Serial ATA RAID Controller User Guide