With a devclass of file, a storage group must have reclamation run regularly, in some cases this can be costly. I'm told that devclass disk will end up fragmenting the storage. This puzzles me. Are TSM file placement algorithms really that bad for disk? It would seem to me that devclass file just puts the file placement work off onto the underlying OS.
The reason I ask is that we have a setup of two TSM servers that all our production servers back up to. Then the two TSM servers back up to TSM servers half a state away. The way off campus servers are two instances on the same physical server. All four servers have their storage groups set up as devclass file. Bandwidth is turning out to be a problem. Backups from the local to remote servers take more than a day and then reclamation of the copypools from the local to remote servers never gets a chance to finish. Result is that the remote servers are full. Wouldn't setting up the remote storage groups as devclass disk at least eliminate reclamation? Would performance eventually suffer because of disk fragmentaion? Thanks in advance for any insight any of you may offer.
