Are the brackup targets compatible?

William Wolf throughnothing at
Thu Aug 13 01:25:44 UTC 2009

On Wed, Aug 12, 2009 at 9:14 PM, Ask Bjørn Hansen<ask at> wrote:
> Hi everyone,
> I'm converting an rsync/rsnapshot backup scheme to use rsnapshot to avoid
> the hassle/cost of moving files around (it's my Aperture Library + raw
> photos backup).
> I'm doing a brackup backup to a Filesystem target now on the "backup host"
> to convert the old backup to Brackup.   I'm planning to then change it to be
> backed up from the "real" host with the Sftp target.   Will that work?  As
> far as I can tell from the code the chunkpath method is the same.  Anything
> else to look out for?
> Three auxiliary questions:
> 1) Shouldn't we have a new release?  The verify script looks useful (to put
> it mildly).

I'd be for it.  There is also a bug in the released version of my
Cloudfiles target that is fixed in svn.  And yes, I love the verify
script and have been using it for a while :)

> 2) I saw in the list archive that there were some (bad) gc bugs late last
> year -- were they all sorted out?

If you are talking about the ones related to encrypted backups, i know
myself and a few others all had patches/code that resolved this issue,
and it looks like revision 239 may have been the commit that resolved
that particular issue:

As for other issues with gc, I'm not sure, this is the one that I knew
about/was concerned with.

> 3) Is there a practical way to re-use chunks from different backup sources;
> or is that how it works by default? (Think backing up a bunch of different
> boxes; many files/chunks will be the same).  I was thinking of using
> rsnapshot (like we do now) to a central host and then 'brackup' that box;
> but that'd probably end up being too many files for brackup to efficiently
> handle.   (Our two rsnapshot backup servers are storing ~1.5TB each with
> about 22M inodes in use each).   I guess the question is: How do you use
> brackup?

Someone correct me if I'm wrong, but I believe some people on this
list have talked about this before, but the main issue was keeping the
inventorydb etc synchronized across all the machines.  The inventorydb
is what brackup uses to "remember" what chunks are already on the
server, so you need to do the backups at different times on each
server, and synchronize the inventorydb's before each sync or
something similar.  Doing all this, I believe it should work.

>  - ask


William Wolf

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