Dell EMC VMAX, Configuration And Best Practices Technical Notes

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NDM MIGRATION OPERATIONS
The migration of an application from the source to the target array is completed using a sequence of user-initiated operations, each
which is fully automated. These migrations are performed at the Storage Group (SG) level. The entire migration of a storage group can
be accomplished with a few clicks in Unisphere or simple, short Solutions Enabler commands that perform the following five operations:

Environment Setup
– Setup configures the migration environment that will be required to migrate any application from the
source array to the target array. It confirms that both the source and target arrays can support the NDM operations. This
includes ensuring that a useable replication pathway for data migration is available between the source and target arrays.
Once the Environment Setup has completed successfully, a Create operation can be run. The environment setup command is
run only once prior to the initial migration between two arrays. All other storage groups migrating between those arrays will use
the same migration environment.

Create
– Solutions Enabler examines a specific application’s storage on the source array and automatically provisions
equivalent storage on the target array. The target devices are assigned the identity of the source devices and are configured
in a pass-through mode that allows the data to be accessed from both the source and target devices.
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After the create operation completes the administrator issues a host rescan to allow the host to discover the paths to
the newly created devices. After this is complete, I/O issued by the application will be directed to either the source or
the target arrays through the host multi-pathing software. HYPERMAX OS will ensure that all I/Os that are directed to
the target by the host are actually serviced by the source array until the cutover.

Cutover
– A cutover operation moves the target devices out of pass-through mode, initiates data synchronization from the
source to the target and makes the paths to the source array inactive so that all I/Os are being serviced by the target array.

Commit
– After the source to target data synchronization is complete and all application data has been migrated to the target
array, a commit operation is performed. During a commit operation, Solutions Enabler completes the migration by releasing
temporary resources allocated to perform the migration, permanently disabling access to the source devices, and assigning
the target device ID to the source devices.

Environment Remove
– This is performed after all migrations have been completed to remove the migration environment. The
array to array connectivity configured for the data migration pathway is removed along with the rest of the infrastructure on
both arrays that was configured by HYPERMAX OS to support the migrations.
Other supported NDM operations

Cancel
– Ends a migration that has not been committed. It removes storage provisioned for the migration on the target array,
releases resources allocated by Solutions Enabler to perform the migration, and places the source devices into the state they
were in before the Create operation was run.

Cancel with Revert -
Run after a cutover operation to move the application’s data access back to the source array from the
target array and cancel the migration.

Recover
– Attempts to complete a failed migration operation. Recover is run following a failure after the cause of the failure,
such as a connectivity issue, has been resolved.

Sync
– Controls the replication from the target side devices to the source side devices after a cutover is done and all data has
been migrated to the target side.

List
– Shows a list of migrations to or from a specified array, with the current status for each.
BENEFITS

Allows migration from VMAX to VMAX3 or VMAX All Flash with hosts and applications completely online

Designed for ease of use with control operations that automate the setup and configuration of the migration environment

Managed by familiar and simple user interfaces via Solutions Enabler and Unisphere for VMAX

Migrations can be easily cancelled and failed back to the source array for any reason prior to commit
MANIPULATION OF DEVICE IDS AND HOST PATHS
NDM is able to migrate data and cutover to the target array non-disruptively by both swapping device IDs between the source and
target devices and manipulating the paths from the ho
st to both arrays. The device ID contains the device’s unique WWN and other
information about it, such as a device identifier that the user has assigned to a device through Solutions Enabler or Unisphere. All of
this information is copied to the target devices.