User Manual

Introduction
1-15
Capacity resource reallocation
If you’d like to add more disks for capacity expansion, you can use disk
group expansion (see 2.7.1 Expanding disk groups on page 2-44).
Resizing logical disks and volumes ( 2.7.4 Expanding the capacity of
logical disks in a disk group on page 2-46 to 2.7.6 Expanding volumes on
page 2-47) can also help you to transfer the unused capacity of a LUN to
others that are desperate for more space without any impact to other
LUNs. If unused space is scattered, you can use disk group
defragmentation (see 2.7.2 Defragmenting disk groups on page 2-44) to
put them together.
RAID level and strip size migration
Changing RAID level of a logical disk (see 2.7.3 Changing RAID level /
stripe size for logical disks on page 2-45) will significantly affect the
performance, reliability, and space utilization. For example, you may add
one disk to a two-disk RAID 1 disk group and change its RAID level to RAID
5, such that you can have a three-disk RAID 5 disk group, offering usable
space of two disks. On the other hand, changing stripe size affects only
the performance, and you may do as many online experiments as
possible to get the performance you want.
Schedule a task
You won’t want the performance degradation during the execution of
the online maintenance utilities, which very like need non-trivial amount
of time. To avoid such impact, you’re allowed to schedule a task
execution to any time you want (see 2.7.14 Schedule task on page 2-55),
like during off-duty hours. You can get event notifications when the task is
done (or unfortunately fails), or at a user-configurable percentage of the
task progress (see 2.7.16 Miscellaneous on page 2-56).