Thank your for pointing that out :-)
You really ought to contact EMC support for an answer on this one:
Contact EMC Retrospect support
The device support database isn't really up-to-date for Retrospect 8. In your favor, though, is that the library is supported both by Retrospect 6 (Mac) and Retrospect 7 (Windows). Library support is pretty good, and you really don't have an oddball library.
Does this additional license apply for the CSM-20? All sorts of annoying additional license schemes made us decide to move away from Time Navigator ;-)
The Advanced Tape Support license is needed if you expect to have multiple tapes active at once (e.g., transfer tape-to-tape, etc.) or multiple concurrently-operating tape destinations, etc. I'm not familiar with the CSM-20. Does it have multiple tape drives? Our library just supports a single tape drive, so I haven't run into this problem. Whether you have multiple tape drives would pretty much answer your question about the Advanced Tape Support add-on. I suggest that you ask this question of EMC Retrospect Support (see link above). They are the authoritative ones on licensing issues like this, not those of us in these user-to-user support forums.
If this catalog is damaged, what is the chances of recvering data from the tape library?
Excellent, providing that the tape media set itself isn't damaged.
To understand why, you need to understand the Retrospect paradigm, which is different from other backup programs. Under the hood, it's a full initial backup plus incrementals backup strategy. The media set (formerly known as a "backup set", formerly known as a "storage set") is really a database, a bucket of bits into which files and metadata is dumped.
The big win with Retrospect comes at restore time, because of its "snapshot" model. Retrospect gives the illusion, by its "snapshot" interface, of showing you the files that were present on the source at the time of each backup session, rather than simply the files backed up during that session. Some of the files present on the source were not backed up during the session because they were already in the backup set (um, media set). But the "catalog" is simply a database index into the media set, pointing to the location of each of the files shown in the session "snapshot". Some of the files shown in the snapshot will have pointers into previous session backups; some of the changed files will have pointers into more recent session backups.
All the catalog does is to permit the "snapshot" model and to enable rapid recovery of files by going directly to the desired files in the media set. With other backup programs, you have to restore the first full backup and then all following incrementals, in order, so that you end up with the right set of files.
If the catalog becomes damaged, Retrospect can recreate it (somewhat slowly - it has to read and digest the entire media set) from the media set.
Clear? Oh, and you can always replicate (copy) the catalogs onto another disk as a precaution. All the catalogs do is save you time (possibly days, if your media set has lots of tapes in it) rebuilding the catalog if it becomes lost (or damaged - Retrospect 8 is not very mature right now. Stuff happens. It's getting better with each bug fix release, but it's far from rock solid right now).
No, providing that you aren't backing up other servers. If Retrospect runs on the server, and doesn't back up any other servers as clients, then it's a "single server" license. If you back up other servers as Retrospect clients (the clients chat with the Retrospect server to do backups for the clients), then you will need a multi-server license.
With "backing up other servers" you mean other Retrospect servers, right? That won't be a problem for us. We will only need one server - at least one running Retrospect.
Luckily we already own an ATTO card :-) Thank you so much for a very thourough reply, Russ. Getting good answers isn't always as easy! Makes a huge difference when choosing between these kinds of products. Thanks!