Burak,

        I don't know about the unlocking them one by one, but what I usually
do when I want to prevent access to the TSM server, I do a 'disable session'
and all client nodes will be unable to connect to do backup/restores.

        When you are done with whatever you wanna do, do a 'enable session'
and all client nodes will have access to the TSM server again. Remember to
do the enable!! I forgot to do it once and one of my server's filesystems
got jammed and caused the application to hang.

Regards,
Eugene