Netbackup DeDupe

NetBackup's dedupe engine was built from the PureDisk technology.  There are however some scalability differences.

NBU 7.x can manage up to 32TB of deduped storage PER media server.  Go beyond that, and you have to stand up another media server, and now your two media servers have no visibility into each other, affecting dedupe rates for the worse over all.  (No global dedupe here!)

PureDisk can support up to 192TB of deduped storage (6 x 32TB) utilizing up to 6 nodes in a PureDisk Cluster.  You do need to follow the HCL to the T to make sure you are supported here.  

Additionally PureDisk is better suited for remote office backups as the fingerprint database is stored locaclly on the client.  Where as for NBU clients, there is a lot of extra traffic over the wire to compare fingerprint hashes with the media server(s).

Is SAN required?  FC and DAS are pretty much all that is supported AFAIK, with Symantec dragging their feet on iSCSI support with some old timers that think it's not robust enough.  (Just let the Veritas guys retire already!)

That said, there is an appeal to their appliances in terms of setup and predicted performance.  Though there are some rather daunting support issues and other items that I'd never allow in a customers enterprise level network, that I've mentioned before in other posts and won't repeat here.  Just do your due diligence, test the respective products, and get the Symantec SE in the room for some very candid questions about where they are good and bad.  A good SE will happily have that conversation with you.  

Make sure to compare against other products too!  Products like Exagrid, DataDomain, Quantum, etc can eliminate much of the support issues I've alluded to.