HP XP20000XP24000 Disk Array - Manual (Page 14)

Notes: When you use Auto LUN for the first time, you must reserve volumes for migration destinations
in advance. These reserved volumes are marked with the icon. When you specify a volume
to be migrated, icons of some reserved volumes ( ) that can be used as a migration destination
will change to the
icons. For details on reserving volumes for migration destinations, see
“ Reserving Migration Destinations For Volumes ” on page 41.
If you specify the volume you want to migrate in the window and click Target, Auto LUN displays the list
of disks of the parity groups that can be used as destinations. If you select the destination disk area
and click Graph, Auto LUN calculates the estimated volume usage rate after migration, and displays the
estimated usage rate in the window (see Figure 6 on page 14). However, Auto LUN cannot estimate
the usage rate of any external volumes. In case of migrating an external volume, the transition of the
external volume usage rate is not displayed even if you click Plan. If the volume usage rate of the
migration source cannot be calculated or if you do not need to know the transition of the usage rate, you
can migrate the volume without displaying the graph.
Auto LUN uses past resource usage rates, hard disk drive type information, and the RAID level to calculate
the estimated usage rate. In the example in Figure 6 on page 14, if the volume 00:03:06 in the parity
group 2-1 is migrated to the reserved volume 01:01 in the parity group 1-2, the parity group 2-1 can
expect 10 percent decrease in the average usage rate (from 21 percent to 11 percent). The destination
parity group 1-2 can expect a 13 percent increase in the average usage rate (from 12 percent to 25
percent). If the estimated result is not satisfactory, you can change the migration destination.
Figure 6 Estimated Usage Rate for Parity Groups
You can create multiple migration plans. If there are any other high-usage volumes, you can continue to
create migration plans. If you finish creating migration plans, you can execute the migration plans to
start volume migrations.
For more detailed information about volume migrations, see “
Migrating Volumes Manually ” on page 42.
Hosts can perform I/O operations on volumes that are being migrated. This section explains why.
Note: The storage system documents (including this manual) use the term source volumes to refer to
volumes that should be migrated. The term target volumes is used for volumes that should become
migration destinations.
About Auto LUN Operations 14