Sometimes you will find that a slave server has not been updated, perhaps due to some transient network problem. One way to get it back in sync, after the network problem has been resolved, of course, is to make some change to the repository and make a push. However, this feels clumsy and inelegant.
Note
At present, Gitolite does not have any way of reporting on push failures, although it does log whatever messages Git itself sends back in the log files. This means admins have to actively monitor the log files for failure, or wait for users to report issues with slaves getting out of sync.
For the aesthetically sensitive, Gitolite has the mirror command. Just log on to the server that contains the master repository, and run gitolite mirror push slavename reponame. This will immediately bring the slave up to date.
If you would like remote users to invoke such updates, simply enable the command for remote use by uncommenting the corresponding line in $HOME/.gitolite.rc.