VTL question

[qwerty]

with a vtl, does we still need a diskpool?
we have 279 clients nodes set up on tsm. backups start at 6pm and are suppsoed to end at 6am.

Currently with the diskpool that we have, 5TB in size, everything gets dumped to the random access disk diskpool "usually" within the 12 hours, well not really, then migrated to a physical tape library.

if we bring in a vtl, management wants to get that 5tb diskpool back for other projects or systms

I have seen 50 sessions running on tsm at the max (i think i have max sessions set to 75 on the tsm server)... does this mean with the diskpool gone, the VTL will need to have 50 virtual tape drives created, or 75 to correspond with the max sessions (am i right in saying each backup session for each node requires its own tapedrive??)

We do not have any lanfree agents anywhere, everything moves over the lan to the TSM server, then out the fiber..

So, do we need to keep our diskpool? or will the VTL and TSM work it out?

 

[Eldoraan]

You're assumption looks correct, if you have 75 clients come in at same time, they all going to want to mount a "tape". So you'll need to define 75+ virtual tape drives on VTL to support it. I can probably reduce the disk pool down, depending on amount each node backs up, and just set migration thresholds low so it moves to the VTL often enough to never fill up. If a smaller disk pool fills, or if you lose the disk pool and have to go direct to VTL, then client sessions will back log waiting for "tape mounts" if all virtual drives are being utilized. That will drag completion window out beyond your 12 hour window.

 

[qwerty]

nexst question

does anyone have a select statement that i can run that will show me tha maximum number of sessions on the server in the last 24 hours?

i am no good at scripting and does not know were to begen on this, or if it is even posible

 

[BBB]

Also, a client backup may use more than one data session if you have tuned the resourceutilisation and maxnummp parameters.

There's no sql query that will give you that info, you'd have to look at the sessions starting and ending times and then calculate how many sessions were active at that point - not fun. Can you just schedule a "q sched" to run every 5 minutes one night and save the output?