HP XP20000XP24000 Disk Array User Manual
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can be executed concurrently changes depending on the number of differential tables that 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
For details on the number of differential table required for migrating a volume, see
Calculating Differential Tables Required for Mainframe Volume Migration
” on page 21 and
Calculating Differential Tables Required for Open-System Volume Migration
•
Manual migration execution. Auto LUN will not execute a manual migration operation when the
current write pending rate for the storage system is 60% or higher.
•
If heavy workloads are imposed on your storage system: Avoid volume migration operations
when heavy workloads are imposed onto your storage system due to I/O requests from hosts.
If you should perform volume migration, the migration could fail. If migration fails, reduce the
workloads on your storage system and then retry volume migration.
Copy Threshold Option
: If the load of storage system increases, host server I/O performance
(response) may be degraded. If Auto LUN performs migration operations when the load of
storage system is heavy, it is more likely that host server I/O performance (response) may be
degraded. The Copy Threshold option temporarily stops Auto LUN operation when the load of
the storage system is heavy. If you set this option in effect, you can minimize the degradation
of host I/O performance (response) by temporarily stopping Auto LUN operations when the
load of the storage system is heavy.
Migration of this volumes is likely to fail when hosts frequently update volumes being migrated. If
you set the Copy Threshold option in effect, this option temporarily stops the copy processing of
Auto LUN when the load of the storage system is overloaded, thus increasing the possibility of
failure in migration of volumes. For this reason, we do not recommend you use this option when
hosts frequently update volumes being migrated.
For information about the setting of the Copy Threshold option, call HP technical support.
Note:
Copy operations that are stopped by the Copy Threshold option will resume when the
load of the storage system become light. If this option is in effect, not only Auto LUN operation
but also the copy operations of the following program products will stop when the load of the
storage system is heavy.
• Business
Copy
• ShadowImage for Mainframe
• Compatible FlashCopy
• Compatible FlashCopy V2
• XP Snapshot
•
Progress Value : It is possible that migration is unfinished even though an Auto LUN window
shows that migration is 100 percent finished. This problem can occur particularly when a volume
with heavy workloads for update I/Os between hosts and the storage system and a volume with
light workloads for update I/Os between hosts and the storage system are migrated together,
a migration plan which the migration of the volumes will not complete even the progress value
becomes 100% may be formed. If this problem occurs, execute either of the following to migrate
the volumes.
• Reduce the workloads for update I/Os between hosts and the storage system and complete
the migration.
• Stop the volume migration for the volume with heavy workloads for update I/Os between
hosts and the storage system, execute a migration of another volume and then retry the
migration which has been stopped.
•
Effects on Other Program Products : When the workloads for update I/Os between hosts and the
storage system are heavy, longer time will be required to complete the volume migration because
the copy of differential data is repeatedly executed. Longer copying time may be required for
other program products when this copy of differential data is executed. See
for the amount of affected copying time of other program product. The copying time of other
program products depends on the number of pairs set to the program product, however, the
copying time may be increased up to twice.
The term other program products refers to the following program products.
• Auto
LUN
• Business
Copy
XP24000 Auto LUN Software User's Guide
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