Your question is a bit like: If you'd take the bus to NY, would you take an inflatable dinghi with you? (If I took it from German I'd better would?).
In the past we used SAMFS. That's a HSM, meaning archiving due to technical reasons. I can't see how to "backup" that with Netbackup.
Then we used Domino Storage Optimizer which archived mail attachements only, on a Centera. Due to it's dedupe/single instancing a backup is not feasible. Just let the Centeras replicate.
We looked at ELO which has a variety of possible hardware for storing it's data.
A project with WORM jukeboxes we canceled – after buying the hardware ...
Nobody was convinced of the return anymore. Part of the problem was that the project was concentrating on the technical issues. The "who" archives "what" and "why" was taken for granted – but not given.
At the moment we use Windream (more a nightmare, decision made on golf course?). That can use e.g. Centera, but can live without. We backup it's data (FS) and it's metadata (SQL).
You can't answer that question in general. There' a lot of software around to fill specific needs. Compliance and space saving (HSM) as two quite different needs e.g. That software then uses different hardware to store it's archives. Dependign on that you can develop a backup strategy like for any other application. In general it's not feasible to backup any dedupe/single instancing hardware.
The decision for an archiving solution is basically one way. There's not really a chance to migrate in ten years to something else.
Most of an archiving system is organization. Therefore it can't (shouldn't) be decided by IT alone.
If the users can't be convinced and still use a file sittig beside them you just burned money for no good reason.
