On Mon, Jun 25, 2007 at 04:43:40PM -0400, Chris Hoogendyk wrote:
> 
> 
> Jon LaBadie wrote:
> > On Mon, Jun 25, 2007 at 12:43:50PM -0400, Chris Hoogendyk wrote:
> > ...
> >   
> >> then I created a dumptype that was the same as my regular dumps but with
> >>
> >> record no
> >> strategy incronly
> >>
> >> I thought this would work, because the incremental would be based on
> >> ufsdump, and it would know there had been a full, even though it was a
> >> different configuration.
> >>
...
> >
> > However, as this was a new config, amanda "knew" there had never been
> > a level 0 for this config.  And of course it must start from a level 0
> > to do the incrementals.  Even on a config meant to do incronly strategy
> > you must do an initial full dump.
> 
> That's sort of what I was guessing with my parenthetical "iff" statement.
> 
...
> 
> And that kind of brings up the question, why "incronly"? Under what
> circumstances would someone find this useful? And how would they use it?

Two possibilities come to mind, one I used in the past.

I had a DLE with just CD .iso images.  Certainly never changing,
but there may be things added to it.  So after the initial full
dump I switched to incronly and it picked up whatever I added.
I abandoned the setup when the full dumps were overwritten.  I
think I then set it up to have a long dumpcycle, basically
matching the tapecycle.

The other idea is to mimic with amanda the ?differential? style
of backups.  I.e. an initial full dump and only changes after
that.  You could take the initial full dump out of rotation.
But amanda still doesn't quite do differentials.  As I under-
stand them, differential don't have levels that go back to a
higher level.  Instead each changed file appears in the backup
tapes just once, after it has changed.


> 
> There seems to be some confusion in the amanda man pages & documentation.
> 
> The man page for amanda.conf.5 says:
> 
> /incronly/
> 
>     Only do incremental dumps. *amadmin force* should be used to tell
>     /Amanda/ that a full dump has been performed off-line, so that it
>     resets to level 1. It is similar to skip-full, but with incronly
>     full dumps may be scheduled manually. Unfortunately, it appears that
>     /Amanda/ will perform full backups with this configuration, which is
>     probably a bug.
> 
> But the man page for amadmin.8 says:
> 
>      force [ hostname [ disks ]* ]+
>          Force the disks on hostname to do a full (level 0)
>          backup during the next Amanda run.
> 
> which actually makes more sense for "force", although I would like to be
> able to tell amanda that there was a full backup done offline.
> 

I've never done it, but I wonder if "force-bump" would allow you
to skip the level 0.

> I can afford to experiment for a while, since my primary backup sequence
> is working; but, at this point, I'm not sure where to go with it. Trying
> to fake out amanda by editing its database seems rather chancy.

Worth a try, let us know.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
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