We used rsync, but it probably make wrong coping on high loaded and large repos. If you did not stop Stash, then rsync possible lost some internal data of git withint Stash. For example, some opened Pull Requests will broken after new Stash instance started. It will complain about merge-base, will reject sha1 hash as unknown, etc.
Is there any ways to perform hot backup on fly? Someone get it worked? Does someone used File Systems with snapshots support?
We perform rsync every one minute, and we used innobackupex database engine for mysql.