A rough outline volume move is ,
#1 Starts with baseline snapshot transfer between the src volume and dest (a temp) volume
#2 Then continously it checks for a snap delta between the source and destination volume and copies the delta
#3 And every time #2 is performed , volume move engine check if the snap delta to be copied will complete within the cutover window that is specified when the volume move was started (default is 30s).
#4 If the snap delta copy can be completed by the cutover window then it will proceed to cutover if not it will go back the copy/replication phase.
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Factors that define volume move entering volume move cutover
* the cutover window that is mentioned
* rate at which the data in the source volume is changing
Note: doesnt depend much on if the data in the volume is deplicated or not.
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Following things can be done
* Check if there are any errors in the volume move (volume move show -instance)
* Since the IO will be fenced during the volume move cutover , if the host/protocol can tolerate IO responded with re-triable reponse , increase the volume move cutover to an higher limit.
* Throttle the IO on the primary volume by setting a QoS policy and this can be removed after the cutover is completed.