On Tue, May 16, 2006 at 11:17:34AM -0400, Jon LaBadie wrote:
> On Tue, May 16, 2006 at 09:53:13AM -0500, Gordon J. Mills III wrote:
> >  here are some of my comments about TSM
> 
> "incremental forever" is a feature I've heard of in some other
> backup systems.  I wouldn't expect that to fit the mold of amanda
> as recovery would then truly demand amanda software and indexes
> to be present.

I've been thinking about a new vtape changer that might make it easy
to do this kind of incremental forever backup.

One issue that I run into: Most of my system have 18-20 virtual tapes.
runtapes is 2, but I really try hard to keep things at one tape.  We
need to kep to weeks of backups.

Suppose some event happens and someone needs to make an emergency
backup of what's on a server, right now.  They run amdump, it clears
the oldest tape.  If this happens too many times in a dumpcycle, oops,
we don't have our two weeks of backups.


I've been thinking about a tape changer that uses a timestamp for the
label.  No tape is ever reused.  When amdump runs, something creates a
new tape, labels it, and loads it.  The backup is done to this tape.

You then have a cronjob that runs nightly to cull old backups.  Give
it a timeframe, it deletes any tapes that are older than the
timeframe.

If you had a model like this, where tapes could stick around forever
if nothing deleted them, you'd just need a flag that a given timestamp
is a full backup and should never be thrown out.


> With many people doing amanda backups
> to vtapes, it would be nice to be able to archive desired
> parts to "offsite" ptapes.

Shouldn't this be easy if you plan to make your vtapes the same size
as your ptapes?

-- 
Ross Vandegrift
ross AT kallisti DOT us

"The good Christian should beware of mathematicians, and all those who
make empty prophecies. The danger already exists that the mathematicians
have made a covenant with the devil to darken the spirit and to confine
man in the bonds of Hell."
        --St. Augustine, De Genesi ad Litteram, Book II, xviii, 37