Finding the connected clients to a Dell PowerScale storage cluster is fairly straightforward, however you should be aware that it only shows clients that have active IO (input-output) operations in flight at the time you run the command. You can still have clients connected, but are idling, so are invisible.
isi statistics client list
You can also specify a specific protocol, e.g. SMB or NFS (v3) too, for example:
isi statistics client list --protocols nfs3
You can also identify the relevant local pool to which a particular client is connecting.
Due to it only “seeing” clients with active IO at the time you ran the command, it is recommended to run the command a number of times over a period of time, then compile the results into a single list so you can minimise the risk you miss a client that wasn’t being very “chatty”.