Re: Incremental Backup of repositories using Git

> On Mon, May 05, 2025 at 02:35:43PM +0000, Akash S wrote:
> > Hi,
> > 
> > Currently we are backing up repositories using the "git clone -bare" command and save it to disk. If we want to restore, we just run git push -mirror from the repo that was saved during the backup.
> > 
> > Currently we are running full backups (run git clone -bare) everyday, which is taking a lot of disk space and time.
> > 
> > Are there any possible ways to backup only the incremental changes of a repository? And somehow construct the whole repository when we want to do a restore from the incremental backups?
> 
> Hello,
> 
> first, to make it easier to update the backup the clone should be done
> with --bare --mirror.
> 
> If your clone ends up having multiple packs and loose objects you
> can reduce its size with
> 
> git --git-dir=/path/to/clone repack -adk
> 
> This should give you a repository with a single pack and no loose
> objects.
> 
> The -k (or --cruft) option is required, using only -ad seems to corrupt
> repositories quite reliably.
> 
> To speed up the clone next time around you can make a copy of the
> previous backup and fetch from the remote repository but because
> there is no safe way I am aware of to eliminate no longer referenced
> objects you will accumulate cruft this way.
> 
> This is now a complete backup, and should be made readonly to not get
> corrupted with further operations.
> 
> The inrementeal backups are somewhat speculative, I have not tested this
> at all.
> 
> You can create a shared clone of the full backup, update the origin URL

> of the shared clone to the remote repository to backup, and do a fetch
> -p (which now should do the right thing because the initial clone was
> set up as mirror).
> 
> To repack you need to use the --local option in addition.
> 
> With this you should have a valid repository for each backup with the
> incremental backups sharing most objects with the full backup.
> 
> These can be inspected with git commands, exported over gitweb, or
> whatever.
> 
> Thanks
> 
> Michal
>