Dell EMC VMAX, Configuration And Best Practices Technical Notes

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APPENDIX C: HOST REBOOTS DURING NDM PROCESS
The following outlines the outcomes of a host reboot either planned or unplanned during each of the discrete steps of the NDM process.
Note: Manual verification of host paths following a reboot of any kind should be undertaken before continuing with a
migration.

Created:
Once the host reboots paths will be re-
detected on the source array. As the rescan of the SAN hadn’t occurred
before the reboot the target paths don’t have to be considered. The migration can continue as normal as a host reboot will
conduct a rescan as part of the boot process and pick up the new paths to the Target. This in turn will move the NDM session
to a Cutover Ready state.

Migrating:
The paths to the source system are not active and a reboot may cause the MP software to permanently remove
the inactive paths to the source array. If the reboot causes the inactive paths to be removed then this will cause a complication
when choosing to cancel the migration and revert back to the source array. Manually rescanning the host while the cancel
–
revert is in the “Wait for the host path discovery on Source” step will reconfigure the removed paths and the migration will
cancel and revert back to the source array. Choosing to continue with synchronization and movement towards the
CutoverSync state will not be affected by the removal of the inactive paths following a reboot.

Cutover Ready
:
Since the paths to both arrays were alive at the time of reboot they will not be affected. Recommendation
at the point is to verify all paths initialize as expected before continuing.

CutoverNoSync :
A reboot during the CutoverNoSync state may cause the MP software to permanently remove the inactive
paths to the source array. The removed paths will not affect the ability to perform a sync
–start to move to the
CutoverSyncing state or the ability to commit the migration.

CutoverSyncing
:
A reboot during the CutoverSyncing state may cause the MP software to permanently remove the
inactive paths to the source array, but will not change the state of the migration session. The Synchronization will continue
reaching a CutoverSync state when completed.

CutoverSync
: A reboot during the CutoverSync state may cause the MP software to permanently remove the inactive paths
to the source array, but will not change the state of the migration session. If a reboot has removed the inactive paths and a
cancel and revert back to the source is desired, then follow the steps documented under the migrating state to process the
cancel
–revert operation. A commit operation will not be affected after the inactive paths have been removed and no special
steps are necessary to commit the migration session.