Misusing Bazaar for Data Backup

[Robert Collins]

On Sun, 2008-08-03 at 11:14 +0200, Moritz Bartl wrote:
> Hallo There!


> The limit for my system seem to be around 300-500MB for one file. When I 
> try to commit a 300MB file, I get the MemoryError described in bug 
> #193685 (in tuned_gzip), while a file with 500MB already breaks knit.py, 
> never reaching tuned_gzip.py:
> ...MemoryError
> 
> Is there any way to approximately tell how big files can be at most, 
> depending on the system specs? How big can a repository be? From what I 
> can tell (in a very limited way), differences between revisions are 
> stored in single .pack files. My initial commit is a 6.2GB .pack file. 
> How will this affect (remote) merging? Would you suggest to also do 
> initial commits incrementally instead of once?

Individual files are held up to four times in memory; .pack files are
just containers - they are written single in a commit and then combined
later to prevent large numbers of files causing many syscalls to be
needed during fetch and tree operations.

> One more thing: Even when I specify individual files for a commit, bzr 
> still scans for changes. Why?

bzr shouldn't be statting all your files, only the individual ones; if
it is statting everything thats a bug. If it shows 'scanning..' that
simply because that phase of the commit still has to happen.

> I have been using Subversion for a while to backup and sync my files, 
> and it didn't have problems, but I'd rather go and use a distributed 
> RCS, because then I can create file revisions even when I'm not online. 
> Any suggestions? Bad idea? I still haven't tried to sync/merge different 
> large repositories...

Should work fine (with the caveat that a single very large file may be
too large to merge).
-Rob
-- 
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