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Promise Technology Pegasus3 R4/R6/R8
RAID Level Migration
The term “Migration” means either or both of the following:
• Change the RAID level of a logical drive.
• Expand the storage capacity of a logical drive.
On Pegasus, RAID level migration is performed on the disk array but it applies to the logical drives.
Migration does not disturb your data. You can access the data while the migration is in progress. When
migration is done, your disk array has a different RAID level and/or a larger capacity.
Migration Requirements
The following conditions affect RAID level migration:
• The disk array and logical drive must show a green check icon.
• The Target disk array may require more physical drives than the Source disk array.
• If the Target disk array requires an EVEN number of physical drives but the Source disk array has
an ODD number, ADD a physical drive as part of the migration process.
• You cannot reduce the number of physical drives in your disk array, even if the Target disk array
requires fewer physical drives than the Source disk array.
• RAID 1 (mirroring) works with two drives only. Only a single-drive RAID 0 disk array can migrate to
RAID 1. Other RAID Levels use too many drives to migrate.
• You cannot migrate a disk array when it is Critical or performing activities such as Synchronizing,
Rebuilding, and PDM.
• For RAID 6, you can add more physical drives but you cannot change the
RAID level.
Source and Target RAID Levels
The tables on the following pages show the migration options for each source logical drive by its RAID
level. The available target RAID levels are shown with their requirements.