Well, in theory you would need as many tape drives defined as you have concurrent backups running at any one time (plus any drives needed for background processes, but you want to avoid background processes that use the VTL during the busiest part of your backup window if you can).
However, whether that is going to work, depends on the throughput your VTL can sustain. If you calculate you need 500MB/sec of backups to meet your window, and your VTL only supports 300MB/sec, then the answer is to start rescheduling your backups. Something I suggest you try, is phasing in your VTL backups gradually. Start with the heavy hitter backups, stuff that you know will push data pretty fast - like TDP's for Oracle & SQL, so you get an idea of what throughput you will get compared to your disk pool. If it's comparable, keep adding VTL drives and backups on those drives, see if it maintains the same throughput you were getting with the disk pool, or starts bogging down as the load increases. (It shouldn't) One thing I have recommended to some customers, is keeping a SMALL diskpool around, to be the target of any problematic or WAN clients that are known to run really really slowly, so you don't have them each tying up a virtual drive. That small diskpool can then migrate out to the VTL, taking only 1-2 virtual drives. Wanda On Wed, Jul 15, 2009 at 6:11 PM, Gill, Geoffrey L. <[email protected] > wrote: > For those with VTL's can you give me an idea of how many tape drives you > have defined? I'm listening to the vendors setup ideas and it seems to > me the 10 tape drives they want to define for TSM sure seems like a low > number when you take into consideration all the things that need to be > done and keeping in mind the disk storage pool goes away and every > backup now goes to tape. > > > > I'd sure like to hear what sort of things you had to do to make things > run smooth. I didn't recommend getting the one we have and certainly > haven't heard anything good about it here or elsewhere. > > > > Thanks, > > > > Geoff Gill > TSM Administrator > PeopleSoft Sr. Systems Administrator > SAIC M/S-B1P > (858)826-4062 (office) > > (858)412-9883 (blackberry) > Email: [email protected] > > >
