02 June 2008


People often state that DPM is a bit of a black box. That it, they know it's working, but aren't really sure what it is doing or who is using it. To help address this problem, over the past week or so I've put together some some DPM monitoring to help visualise all of the information which is usually locked in the MySQL database. Hopefully, this will give sites an idea of what DPM is doing and make it easier to debug problems with data access.

The system works using GraphTool (I've mentioned this numerous times before) and is heavily influenced by Brian Bockleman's dCache monitoring tool. I have constructed a variety of queries which pull information directly from the DPM MySQL database about transfer requests. The monitoring is basically a set of python scripts and xml files. To ease installation and help resolve the dependencies, I've packaged (again, thanks Brian) the monitoring up into an rpm called GridppDpmMonitor and hosted it in the HEPiX sys-man yum repository. Instructions for configuration are here, along with some example plots.

I'm still working out exactly what plots we want to see and constructing the appropriate SQL queries. It's a beta (i.e. not perfect) release but I would appreciate any comments you have. The system is already running at Edinburgh, Durham and Cambridge (thanks Phil and Santanu!).

You should note that getting a transfer rate plot doesn't actually appear to be possible. If anyone can work out a way of doing it from the dpm_db tables then let me know. Also, having this monitoring linked into Nagios would be great, but that is something for the future.

As always, contributions are welcome!