Notes on performing data migration, Conditions for data migration, 78 conditions for data migration – HP XP P9000 Command View Advanced Edition Software User Manual
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During migration, data can still be accessed.
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When data migration is completed normally, the LDEV ID and host I/O of the migration source
volumes are changed to those of the migration target volumes. The procedure for accessing migrated
data is not changed before or after migration.
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If linked with HP StorageWorks P9000 Performance Advisor software, parity group busy rate for
the migration source volume and migration target volume can be checked.
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After migrating, you can delete the data of the source volumes.
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After volumes are migrated to a THP/Smart volumes, unused capacity in the target volumes is re-
turned to the pool (zero page reclaim) if the zero page reclaim option is on.
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You cannot work with volumes (such as copy pair or volume allocation) until the migration tasks
are completed.
You must have a Tiered Storage Manager license registered to perform Data Migration.
For details about data migration in Legacy mode, using migration groups earlier than v7.1.1, see
“
Notes on performing data migration
The number of volumes that are candidates for migration target volumes are narrowed down and
displayed when selecting a migration target volume. If you want to display all the volumes, in the
migration.properties
file on the Device Manager server set a value for the
migration.plan.candidateVolumeCountLimit
property.
For details on the properties file, refer to the HP P9000 Command View Advanced Edition Suite
Software Administrator Guide. To avoid insufficient memory, we recommend that you use the default.
The maximum number of volumes that can be displayed as migration target candidates is 2,000
volumes. Exceeding this value will produce an error.
The maximum number of volumes that can be displayed as migration source candidates is 500
volumes. Exceeding this value will produce an error.
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 performing
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 on the migration target cannot be ensured. Therefore, data
migration must be performed again.
If a data migration fails, and operations for the migration target such as re-execution of data migration
and volume allocation cannot be performed, the storage system must be refreshed.
Conditions for data migration
Data migration conditions include conditions that apply to all volumes (volume migration requirements),
and conditions that depend on the type of volume (volume migration requirements related to volume
type).
For some volumes, when you try to select those volumes as migration-source volumes, the reasons
why they cannot be selected as migration-source volumes are displayed on-screen.
Managing storage resources in a SAN environment
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