For one of our customers, we are using the fabulous Dropbox tool to perform synchronisation (in this case between a website and the client's workstation).

In order to monitor that Dropbox is running correctly we've written this Nagios plugin which we are using together with Opsview which is our preferred Nagios implementation at the moment.

We use Opsview as it is far easier to configure that the raw Nagios configuration files and has various improvements out of the box. At some point we may re-evaluate this in order to leverage Puppet integration better.

Just click to down the Nagios Dropbox plugin.