HP StorageWorks Auto LUN XP user guide for the XP128/XP1024 (December 2005)

Auto LUN XP user guide for the XP128/XP1024 17
• Volumes Continuous Access XP Journal uses
• Volumes specified with the Read Only or Protect attribute
• Volumes that Volume Security disabled for use as secondary volumes
• Volumes that LUN Security XP Extension specified as Read Only or Protect or disabled for use as
secondary volumes
• Volumes reserved by a migration program other than Volume Migration
Number of volumes
In manual migrations, the number of migration plans that can be executed concurrently might be restricted,
depending on use of other Command View XP or XP Remote Web Console programs and emulation types
and sizes of migrated volumes. Therefore, the number of migration plans that can be executed concurrently
is not constant.
A maximum of 36 Auto LUN XP copy operations can be requested at the same time. Auto LUN XP performs
migration operations sequentially (one volume at a time).
The maximum number of Auto LUN XP copy operations plus BC pairs is 1024.
Auto migration planning
Auto LUN XP will not plan an auto migration 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)
• Auto LUN XP cannot estimate the usage rate for the target parity group because of some condition (for
example, invalid monitor data)
• The estimated usage of the target parity group or volume is over the user-specified maximum disk usage
value for that HDD class
• The estimated performance improvement is not large enough
Auto migration execution
Auto LUN XP 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 usage rate for auto migration
• The current write pending rate for the disk array is 60% or higher
Manual migration execution
Auto LUN XP will execute a manual migration operation when the current write pending rate for the disk
array is 60% or higher.
Maintenance
Do not perform Auto LUN XP migration operations during disk array maintenance activities (for example,
cache or drive installation, replacement, or de-installation).
Auto migration parameters
Auto migration parameters are initialized when the disk array configuration is changed (for example,
when new drives or LDEVs are installed). Parameters include disk usage limit and migration time. After a
change is made to the subsystem configuration, you must specify auto migration parameters again.
Powering off disk arrays
To turn the power off at the disk array, ensure that volume migration is finished. If migration is not finished,
HP strongly recommends that you do not turn off the power until the migration is finished.
If you turn the power off while migration is in progress, data migration stops and some of the data are not
migrated. If you turn the power on later, Auto LUN XP resumes data migration. If data remains in shared
memory, which is volatile memory, Auto LUN XP attempts to copy only data that have not been migrated to
the migration destination. However, if data is lost from shared memory, Auto LUN XP attempts to copy all