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NDM performs the data migration and device ID swap without the host being aware. The path management changes appear as either
the addition of paths or the removal of paths to the existing source device. To the host and application, there is no change in the device
that it is accessing and access to the device is maintained throughout the entire migration process.
SUPPORTED DISTANCE BETWEEN THE SOURCE AND TARGET
NDM is supported across SRDF synchronous distance. However, because of the requirement that the host see both the source and
target storage, migrations will typically be performed between arrays within a data center.
EFFECTS ON DEVICES AND EXISTING REPLICATION SESSIONS
Devices that are included in migration session in both the source array can remain in existing replication sessions throughout the
migration. NDM will evaluate the states of any current replication sessions before proceeding with the migration and make sure that
they are in the proper state to allow the migration to succeed.
Though existing replication sessions can be left in place during the migration, replication relationships will not be migrated to the target
array. These replication resources will need to be created on the target array, if required, at the appropriate point in the migration.
For example, SRDF replication can be configured between the target array and its remote array while in the CutoverSyncing state or
after the CutoverSync state is reached. The new DR RDF pairs can then be allowed to synchronize before the Commit so that DR is
maintained throughout the migration. SRDF can also be setup in the CutoverNoSync state, which is reached when the sync command
is used to stop replication. For local Snap/VX sessions running against the source volumes, existing session on the source array can
continue as normal during the migration and new sessions can also be created at the same time that the new SRDF replication is
configured.
Storage on the source and target arrays that is involved in the migration of an application should never be altered, and the migration
resources should not be managed, outside of the NDM commands. If any changes in the migration session are detected when a
migration operation is executed, the operation will be blocked until the changes that were made are undone, allowing the migration
operation to proceed as expected.
SRDF Restrictions:
Migrating devices cannot be R2 devices.
Cannot be concurrent RDF devices.
The devices must not be enabled for RDF Consistency.
The R1 may not be part of an SRDF/Star configuration.
The RDF relationship may not be part of an SRDF/Metro configuration.
SRDF must not be replicating data from the target to the source, such as during an in-progress restore.
TimeFinder Restrictions:
The migration source or target may not be the target of a TimeFinder copy session.
SRDF must not be replicating data from a local replication operation, such as during an in-progress TimeFinder restore.
Open Replicator Restrictions:
The migration source device may not be the control device in an Open Replicator pull operation.
Open Replicator must not be replicating data from a remote device to a control device, such as during an in-progress restore.
Содержание VMAX
Страница 6: ...6 Figure 1 NDM Overview ...
Страница 60: ...60 Click the angle bracket next to Add to Job List and click Run Now ...
Страница 65: ...65 Source device ...
Страница 72: ...72 Source Device ...
Страница 73: ...73 Target Device ...
Страница 75: ...75 Click the angle bracket next to Add to Job List and click Run Now ...