The RAID subsystem controller redistributes the original volume set over the
original and newly added disks, using the same fault-tolerance configuration.
The unused capacity on the expand raid set can then be used to create an
additional volume sets, with a different fault tolerance setting if user need to
change.
1.4.3.4 Online RAID Level and Stripe Size Migration
User can change both the RAID level and stripe size of an existing volume set,
while the server is online and the volume set is in use. Online RAID level/stripe
size migration can prove helpful during performance tuning activities as well as
in the event that additional physical disks are added to the RAID subsystem.
For example, in a system using two drives in RAID level 1, you could add
capacity and retain fault tolerance by adding one drive. With the addition of
third disk, you have the option of adding this disk to your existing RAID logical
drive and migrating from RAID level 1 to 5. The result would be parity fault
tolerance and double the available capacity without taking the system off.