Chapter 8. Configuring Units154 3ware Serial ATA RAID Controller User GuideTo change the RAID level of a unit1 In 3DM 2, choose Management > Maintenance.2 In the Unit Maintenance table on the Maintenance Page, select the unit forwhich you wish to change the RAID level, by checking the box next tothe Unit ID.3 Click the Migrate Unit button.The Migrate dialog box appears.4 Select any drives to be added to the unit.5 Select the new RAID level.6 Optionally, select a new Stripe size.7 Click OK.The Maintenance page updates to show the new unit and the Migrationprogress.8 Inform the operating system of the change, as described below.Note: You can only migrate a unit to a RAID level that has thesame or more capacity as the existing one. A four-drive RAID 5unit can migrate to a four-drive RAID 0, but a four-drive RAID 0unit cannot migrate to a four-drive RAID 5, without adding anotherdrive, due to the need for additional storage capacity for parity bits.Expanding Unit CapacityYou can expand a unit's capacity by adding one or more drives to it withoutchanging the RAID level, except for singles and RAID 1 units. (Since a singlecan only have one drive, and a RAID 1 can only have two drives, if you add adrive to either, the RAID level must be changed.)Expanding unit capacity can be accomplished while the unit is online, withoutexperiencing any data loss. This process is also referred to as Online CapacityExpansion (OCE).To expand a unit’s capacity1 In 3DM 2, choose Management > Maintenance.2 In the Unit Maintenance table on the Maintenace Page, select the unit youwish to expand by checking the box next to the Unit ID.
