I would guess the server is figuring out what tape to mount next.  Can you
measure server cpu% and i/o during that time?

Robin Sharpe
Berlex Labs



                    Jeff Connor
                    <connorj@NIAGARAM
                    OHAWK.COM>        To:    ADSM-L AT VM.MARIST DOT EDU
                                      cc:    (bcc: Robin Sharpe/WA/USR/SHG)
                    01/15/02 11:05 AM Subject:
                    Please respond to        "Think time" between switching 
tapes during restore
                    "ADSM: Dist Stor
                    Manager"







Does anyone know what TSM is doing just prior to switching tapes
during a restore?

First our environment:

TSM for AIX V4.1.4.0
AIX 4.3.3 on an H80
Client being restored is a Windows 4.0 server sp6a
   two 700MHz xeon with 512MB RAM
TSM Windows client 4.2.1.15
100Mbit Ethernet nic and switch locked at 100Mbit full duplex
3494 with 3590 Fibre Channel attached drives using K tapes.

  The specifics of what we are seeing is:

1. Nothing else is running on the TSM server except our restore
    session.
2. The DSMC process, viewed through task manager on the
    Windows client shows 0 to 1% CPU and system idle 99%+
3. Q SESS from the admin CLI shows the restore session in a RUN state
    with send and recv byte counts not moving.
4. After the session sits in a RUN state for up to 5 minutes a state change
    for the session to MEDIAW occurs.  A new tape is mounted in a minute
    or less and the session continues.

So my question is, what is going on during that time between tapes when the
session appears to halt but says it's running?  Anyone else seen this
behavior?  It does not appear to be a client or server resource
shortage of any kind.

Thanks
Jeff Connor

Niagara Mohawk Power Corp