HP StorageWorks XP Remote Web Console Software - Manual (Page 22)

◦ Volumes on which RAID Manager is performing volume migration operations
◦ Volumes that form an XP Snapshot pair
◦ Pool volumes used by XP Thin Provisioning
◦ Volumes that are in an abnormal or inaccessible condition (for example, pinned track,
fenced)
◦ Volumes on which Quick Format is being performed
◦ System disks
◦ Quorum disks
You can also reserve external volumes as target volumes.
You can also reserve XP Thin Provisioning virtual volumes as target volumes. However, an XP
Thin Provisioning virtual volume that is related to the same pool as the source volume cannot
be specified as the target volume.
•
Number of migration plans that can be executed concurrently: In manual migration, the number
of migration plans that can be executed concurrently might be restricted depending on the
usage of other storage system programs, and also depending on the emulation types and
sizes of the migrated volumes.
XP Auto LUN uses the term differential tables to manage differentials incurred by the write
operation while migrating volumes. Differential tables are the resources shared by XP Snapshot,
XP Auto LUN, XP Business Copy, ShadowImage for Mainframe, HP StorageWorks XP for
FlashCopy Mirroring Software, and HP StorageWorks XP for FlashCopy Mirroring V2 Software.
Therefore, the maximum number of differential tables that XP Auto LUN can use is the number
of total differential tables in the storage system minus the number of differential tables used
by other programs.
Moreover, the number of differential tables needed to migrate one volume differs depending
on the emulation type and size of the volume. Thus, the maximum number of migration plans
that can be executed concurrently changes depending on the number of differential tables
that XP Auto LUN can use, and depending on the emulation types and sizes of volumes to be
migrated.
For details on how to calculate the number of migration plans that can be executed concurrently,
see
“How to Calculate the Number of Concurrent Migration Plans” (page 25) . For details on
the number of differential tables required for migrating a volume, see “Calculating Differential
Tables Required for Mainframe Volume Migration” (page 26) and “Calculating Differential
Tables Required for Open-System Volume Migration” (page 27) .
•
Auto migration planning. XP Auto LUN will not plan an auto migration operation when:
There is no reserve volume with the same emulation type and capacity as the source
volume in the same or next higher/lower HDD class (auto migration is performed only
between consecutive classes or within the same class). ◦
◦ The usage rate for the target parity group cannot be estimated because some condition
is preventing XP Auto LUN from estimating expected usage (for example, invalid monitor
data).
◦ The estimated usage of the target parity group or volume is over the user-specified
maximum disk utilization value for that HDD class.
◦ The estimated performance improvement is not large enough.
•
Auto migration execution. XP Auto LUN will not execute an auto migration operation when:
The current usage (last 15 minutes) of the source or target parity group or volume is over
the maximum disk utilization rate for auto migration. ◦
◦ The current write pending rate for the storage system is 60% or higher.
22 About XP Auto LUN Operations