I am trying to get what is the recommended command to figure out if the node is currently being accessed via SMB client so that in the event of maintenance on a node we can assess if it be a good idea to take it down.
I found this out there already, but it isn't answering the question: https://community.emc.com/message/924651#924651
imho there is no right way of determining the value of "good idea to reboot".
depending on your workflow the number of users is a interesting value. in other cases it's more a question of traffic.
i would begin:
isi statistics pstat --protocol=smb2
to see how many protocol traffic is going on, combined with Network Output / disk I/O i get a Feeling HOW MUCH the smb users are doing.
with isi smb sessions list
i can look WHO is doing stuff (maybe my CEO is reading his pdf-newspaper may be more important than a higher number of "normal folks")
with isi smb openfiles list
i can look WHAT these People are doing (are they all just reading a Manual or are they doing some DNS-sequencing)
with isi statistics client
i can look further in HOW the used tools are doing the workload. This would be quite uninteresting in case of maintenance and more something for workload / performance analytics.
One "gotcha" with 'isi smb openfiles list' is that it only reports on open files in the System access zone. So if your CEO's newspaper is in a non-System access zone, the open file entry won't be returned with that command.
There's a workaround in this thread: Output of "isi smb sessions/openfiles list" Access Zone aware?