You are going to be looking for open files on every single node using "isi smb openfiles list" and then closing.  Are you going to be looking for sessions using "isi smb sessions" and deleting them?  Ultimately it's your call but I think you are creating more work for yourself then needed.  Schedule downtime with your users, tell them to save their work and then delete the share.  Do your SyncIQ work .etc and you are done.  You can easily document the share settings and put them back after the fact.
Hi, I have some exports & shares which I am planning to migrate to another Isilon using SyncIQ. During cutover, what is the best way to disable any user IO access for source exports/shares ? I know there is option to disable protocol for entire Isilon but in my case, I just want to disable user access for selective exports/shares. Pls suggest. Thanks  
Isilon: disable user access for shares/exports