The problem with incremental backups is that it
eventually runs out of levels. It works fine for the
first few days, while the level increases daily. But
what happens once you reach 9?! It stays at 9 and
does a differential compared to the last 8,  so it
will backup more and more days, until, one day you
run out of tape. 

The only workaround I can think of is to wrap a
script around amdump to only backup the directory
that was changed in the last day. But this becomes
equivalent to me managing the dumps, which seems to
defeat the purpose of using Amanda in the first place :)

Cheers,
Milos


----- Original Message -----
From: Thomas Hu <thomash AT date DOT com>
Date: Tuesday, March 18, 2003 3:08 pm
Subject: RE: differential vs incremental backups

> Dereferencing the symlinks is up to tar or gtar
and I believe can be
> specified within amanda configuration. However,
extra caution has 
> to be
> taken in recovering as by default the link would
be disconnected and
> filled in with actual data. Two issues can merge
up. One is the disk
> space of filesystem where the links are. The other
is you still need
> manually copy the data to where it is supposed to be.
> 
> For production env, got to have a better way.
Carefully organizing the
> filesystem/directory architecture and a few cron
job lines would work.
> Or simple incremental backup of the whole
filesystem would work too.
> 
> Thomas
> 
> 
> 
> 
> 
> -----Original Message-----
> From: owner-amanda-users AT amanda DOT org
> [mailto:owner-amanda-users AT amanda DOT org] On Behalf
Of Bernhard Beck
> Sent: Tuesday, March 18, 2003 2:19 PM
> To: mbrkic AT farelogix DOT com; amanda-users AT amanda DOT org
> Subject: RE: differential vs incremental backups
> 
> I'm looking at a similar problem here. One of the
ideas we came up 
> withwas
> to create a current directory (e.g.
/dbdumps/current) which gets 
> backedup
> by Amanda. Inside are symlinks to the actual dump
files in the daily
> directories (/dbdumps/01, /dbdumps/02, ...). Your
daily DB dump script
> updates the symlinks in current when it is done.
> 
> We haven't implemented this yet, but Amanda should
dereference the
> symlinks
> and back up the right data. This way you always
access the same 
> DLE and
> get
> your normal Amanda behaviour.
> 
> In your case, depending on what your dumps look
like, you could 
> run diff
> on
> today's and yesterday's  dump and only back up the
result (Amanda 
> alwaysbacks up whole files).
> In our environment this doesn't really matter
though, since the dump
> files
> are changing pretty dramatically at times, so an
incremental would 
> looklike
> a level 0 anyway most of the time.
> 
> Personally, I'd feel safer with just backing up
the whole dump 
> every day
> and
> leave the job to Amanda.
> 
> Your milage may vary of course.
> 
> Bernhard
> 
> > -----Original Message-----
> > From: owner-amanda-users AT amanda DOT org
> > [mailto:owner-amanda-users AT amanda DOT org]On Behalf Of
> mbrkic AT farelogix DOT com
> > Sent: Tuesday, March 18, 2003 9:14 AM
> > To: amanda-users AT amanda DOT org
> > Subject: differential vs incremental backups
> >
> >
> > Hi,
> > I have a disk that is a cache for database backups
> > and is a set of 30 directories with database exports
> > of the last 30 days. I want to use Amanda to backup
> > ONLY the latest written directory every night,
> > without ever doing a full backup of the whole disk
> > (it is too big
> > to fit on one tape! :(  )
> >
> > In other words, is there a way to tell Amanda to
> > always back-up only the changes from the last run
> > regardless of dump levels. Equivalently, is
there a way
> > to fool Amanda into thinking that a full backup was
> > done every night, after the level 1 completes
> > successfully.
> >
> > Any other ideas would be appreciated!
> >
> > Cheers,
> > Milos
> >
> >
> >
> 
>