svnsync and commit metadata

Hello,

We are trying to write a check for our monitoring system which asserts
that an SVN mirror is up to date with the master. We do currently
have a check looking at the youngest revision number/age on the master
and mirror, however, this wrongly asserts that the mirror is out of
sync during the brief window when the mirror hasn't caught up.

We would like to find a way of inspecting the time of a given commit
being successfully synchronised to a mirror as opposed to the
timestamp of the commit itself. We think that this might be stored as
metadata in the subversion filesystem. Alternatively, is it possible
to inspect the SVN repo on the mirror and determine the time of the
most recent successful svnsync? I am aware that we could check the
return code of svnsync running on the master, however, we need to be
able to check this on the mirror end of the process.

We would appreciate advice anyone has with this situation, or tips
from anyone who has dealt with anything similar.

Many thanks,
James.

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