> I think that my words have been taken out of context. I know you cant > and shouldn't mix retentions on media which is why i find it hard that > people use 1 media pool for all backups. From that i would assume they > have the same retention for all backups. This in my opinion which is > only my opinion is a bad idea. > > To give advise to the original thread i was saying that one > volume pool > for all backups is perhaps not the right way to do things and i was > surprised by the number of people who seemed to adopt it. I > asked about > mixed retentions as people with 1 volume pool cannot ( safely ) then > have a full backup with a different retention than say a > cumulative backup.
Dave, perhaps I'm dense, but I read the above the same as I read your original statement: it seems you are saying that a 1-month-retention full can wind up on the same tape as a 1-week-retention cumulative. There's no "safely" about it--that _does_ _not_ _happen_ unless you force it with use_multiple_retentions_per_media. Has nothing at all to do with volume pools. Please, what am I misunderstanding about what you are saying? > > What about them? NetBackup *never* puts different > retentions on a tape > > unless you force it to with the > MULTIPLE_RETENTIONS_PER_MEDIA directive > > (and there are very few situations where that's a good idea). And someone asked when that would ever be a good idea. Two that I've found are o small robots. Maybe it's worth having some full, out-of-the-robot tapes with mixed retentions sitting around until the longest/newest image on it expires versus having, say, eight partial tapes clogging up slots in the robot (say, MediaA and MediaB, each backing up clients with 1-week and 1-month retentions in two pools. Throw in mux/non-multiplexed, a few more pools, a few special retentions, another media server, and ... well, a 30-tape robot just won't cut it for that customer. If you allow multiple retentions, you free up precious slots. o moving day. A couple of clients are moving to another NetBackup domain, or maybe you're sending backups to a DR site. If you make, or dup, their dailies, weeklies and last monthly (w/different retentions), it's three tapes--or one if you put them all on one tape. In short, "multiple retentions per media" doesn't hurt a darned thing, ever. It just means that a tape of 1-week-retention dailies that has a 1-month-retention weekly on it at the end won't become available for a month, rather than a week. And _that_ is intrinsically no different than the "waste" of older images at the beginning of a single-retention tape being held hostage to the expiration time of the last image. _______________________________________________ Veritas-bu maillist - Veritas-bu@mailman.eng.auburn.edu http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu