Looking for way to monitor dsync, confirm it is or isn't running

[Rich Wales]

I am syncing two Dovecot sites using the dsync function.

I would like to be able to run some sort of periodic health check to
confirm that dsync is (or is not) running properly between the two
sites, and alert me if dsync is failing or lagging excessively.

Does anyone know of a tool to do this?  (If possible, something I can
set up to run periodically in Nagios?)

Thanks for any suggestions.

Rich Wales
richw at richw.org