2015/09/20: Mirroring svn repositories

Mirroring an svn repository is quite simple.

• If the machine has direct read access to the repository, e.g., because the machine is usually online, then the tool to use is svnsync. To start the process, call svnsync init once. To keep the repository up to date, call svnsync sync each time the mirror has to be updated. However, there are some things to keep in mind.
  • svnsync init does not create a repository. Instead, it expects an existing to be provided. Moreover, this repository has to allow such operations: the hooks/pre-revprop-change hook has to be executable and return 0 whenever such operations are legitimate.
  • svnsync init does not fetch any commits. So, to actually copy the remote repository, it is necessary to call svnsync sync afterwards.
• If the machine can only receive files (e.g., via uucp or by carrying disks around), but otherwise is offline, then it is best to first create a mirror on an online machine (as just described) and there create "dumps". These can be generated with svnadmin dump and a version range can be specified (note: both, the first and the last version specified in the range, will be part of the dump). Dumps can be applied with svnadmin load. For the initial replication, it is usually faster to create a tar ball.