HP XP Array Manager Software - Manual (Page 48)

• Data migration tasks take a long time from start of execution to completion. This might affect the
performance of access from hosts to target volumes. To avoid executing such tasks while the access
frequency is high, check the time required to complete the tasks and set a task execution schedule
before registering the tasks. Actual required time might differ considerably in cases such as per-
forming migration for the first time, migrating a volume smaller than 170 GB, or migrating many
volumes at the same time.
• When storage systems or hosts are under a heavy load, migration might fail. In this case, reduce
the load on the storage systems, and then perform data migration again.
• If data migration fails, the integrity of data at the migration target cannot be ensured. Therefore,
data migration must be performed again.
• If operations on a migration target volume, such as the re-execution of data migration and volume
allocation, cannot be performed after the data migration fails, the storage system must be refreshed.
Values for ensuring the operation of Tiered Storage Manager and recommended
values
The values below ensure the operation of Tiered Storage Manager. Performance might slow down
or memory might become insufficient if a value exceeds these values.
Table 1 Tiered Storage Manager Values
Recommended value Value for which performance is ensured Item
30 or less 100
Number of tiers in a
single storage system
1,000 or less 1,300
Number of unused
volumes a tier
5 or less maximum of 500
Number of volumes that
can be migrated at once
N/A maximum of 2,000
Number of volumes that
can be displayed as can-
didates for migration tar-
get volumes
Conditions for migrating data
Before migrating data, verify the following:
• An HP StorageWorks P9000 Tiered Storage Manager software license is registered.
• An external connection is set up to a HP P9500 (HP StorageWorks P9500 Disk Array), XP24000/
XP20000, or XP12000/XP10000/SVS200 when data is migrated while storage systems are
being migrated.
• Determine the migration source host, logical group, or storage system.
• You know which data to migrate and which storage systems they belong to.
• Determine the migration target THP pool or tier.
Conditions of volumes that can be migrated:
• The emulation type, number of blocks, and size are the same for the source and target migration
volumes. However, note the following exceptions:
Setting up and operating a SAN environment 48