Catalyst only has benefits for specific backup clients. If you are not using backup software which explicitly supports Catalyst, there is no benefit. The benefit of Catalyst is that it does the dedup on the client machine, not on the StoreOnce, so there is less network traffic. It doesn't make the dedup more efficient on the StoreOnce. Catalyst also requires separate NAS shares. So if you mix Catalyst and non-Catalyst on the same StoreOnce, they do not share dedup information. We have regular NAS shares with 30 generations of tapes that have dedup ration of > 19. It works pretty well. As far as compression, I think it is best to turn off compression for better dedup performance. Maybe others have experience with this, but we have compression turned off.
