Eliza,
We are using 25 GB volumes right now without any issues but we are still 
collocateing by node.  We are evaluting the savings of using smaller volumes 
when we move to noncollocated storage pools.  I agree that it doesn't make 
sense to collocate file device class pools but managment wouldn't let us change 
that at first.

If you are talking about a Windows server then you need to think about file 
handles and their effect on the 256 MB of nonpagged memory.  Also, the size of 
your MFT should be considered.  Using more smaller files will have an effect on 
these things.

I think as more and more of us implement these solutions we will have more 
collective knowledge from which to guide these decisions.

Again, 25 GB volumes have been working well for us for nearly 8 months.  We set 
our storage pools to relaim=30.  We run expiration at 6:00 AM which starts a 
reclamation process soon after. We never have reclamation processes running 
past 8:30 AM.  We have run many restores and have been extremely pleased with 
our speeds, much faster than tape for servers with many small files.



"Rushforth, Tim" <TRushforth AT WINNIPEG DOT CA> wrote:
Eliza:

At the Disk only Backups Technical Exchange, IBM recommended 2-4 GB volume
size. (This was stated by the presenter, it was not written on the PDF
presentation.) We started with 25 GB volumes and have now switched to 4 GB
volumes.

Using smaller volume sizes allows a better utilization of space and
increases restore performance with multi-session restore. (Also helps
eliminate contention if multiple clients are restoring from the same volume)


Tim Rushforth
City of Winnipeg