A locally accessed subversion repository is a bit fragile on unix permissions.
It might work fine for first 1000 revisions, and then suddenly all svn operations fail with an error:
svn: Can't move '/home/svn/...' to '/home/svn/...': Permission denied
Fortunately this is easy to fix by making sure the
- shared directories have group 'svn'
- shared directories have mode 2775
- and that the svn is always invoked with umask 002
The umask is easy to enforce by installing a wrapper for the svn binary, which sets the umask and exec's the original binary.