On Tue, Jul 25, 2006 at 03:19:31PM -0400, Jon LaBadie wrote:
> > Is there such a limit in Amanda anywhere?
> 
> In planner.c there is code deciding upon level that basically
> says "if I'm thinking of doing level 9, don't even consider anything
> higher, return level 9 as the decision".
> 
> And in lots of other code, like reports, cleanup, amadmin, ...
> there are things like "for (level = 0; level <= 9; level++)".

Makes sense - Amanda runs on plenty of platforms where dump levels
higher than 9 probably freak out the software.

> My take from your questions is that you want or expect to get high
> incremental levels.  Your needs may differ of course, but I'm happy
> that my incrementals seldom even get to level 3.  It reduces the
> number of tapes needed for a recovery and changed data often appears
> in multiple incrementals at the same level for redundancy.

With vtapes, there's not much of a downside to having higher levels.
No physical tape switching means that I just have to repoint to a
different directory for the next tape.

In that sense, having dumps hit levels 5 and 6 is a quite good thing.
The space savings from going higher than that are diminishing returns
for the servers I run, but I can imagine a highly volatile load where
that had good benefits.

> Perhaps very important for
> your need might be bumpdays which defaults to "2 days".  This is the
> minimum number of dumps at each incremental level before amanda will
> bump to the next level.  Dropping it to 1 is a good first step.

Dropping bumpdays to 1 made a major difference in terms of space usage
for me.  It helped a lot.  The other parameter that helped me a lot
was bumpmult.  It had bee originaly configured as 4 (not sure if
that's a default or not) and I dropped it to 2.  This helps Amanda
spend less time on larger level 0 and 1 dumps and more quickly gets us
to the more space efficient levels.



-- 
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