> The client reportedly has an ADSM server/library with 4 tape drives in it.
> In the past they were not using disk storage pools and he claims that they
> never had contention problems with the tape drives.

I would say that old the old hardware the management classes were set
to send the files to disk and not directly to tape.

If a client is sending directly to tape the client has EXCLUSIVE
access to the tape drive.  The *SM server will not interleave clients
onto tapes when the files are arriving.

(From memory, if you want that feature, you need to upgrade to Legato ;-) ;-))


In the 3.1.x Admin Guide (Chapter 5, Using Removable Media)

        Client Back Up Directly To Tape
        ...
        Key Choice: If you backup directly to tape, the number of
        clients that can back up data at the same time is equal to the
        number of drives available to the storage pool (through the
        mount limit of the device class).



> Any ideas on how to reconfigure the server so that it will accept more than
> 4 sessions would be appreciated.


If you have more sessions that available drives, the extra sessions
will wait until a drive becomes free.

If the sessions are terminating, then you probably have the higher
mount limit set higher than the number of real drives.  *SM is saying
"you said there was a drive, it was not there, I will be unhappy now."

Make sure the mountlimit is set to match the number of real drives.
Use "query devclass f=d" and look for the MOUNTLIMIT line.

You probably want to set it to "DRIVES" which will always be the
number of online drives in the library.



Russell