22 February 2008

dCache configuration, graphviz style

I don't know about anyone else, but I'm fed up having to try and debug different site's PoolManager.conf files, especially with all this LinkGroup stuff going on. I find it too too hard to manually parse a file when it stretches to 100's of lines, making it virtually impossible to know if there are any mistakes.

In an effort to try and improve the situation, I put together a little python script last night that converts a PoolManager.conf into a .dot file. This can then be processed by GraphViz to produce a structured graph of the dCache configuration. You can see some examples of currently active dCache configurations here. The above plot shows the config at Edinburgh.

I have been creating both directional (dot) and undirectional (neato) graphs. At the moment, the most useful one is the dot plot. I'm still exploring what neato can be used for.

I think the fact that we even have to consider looking at things this way tells you two things:

1. dCache is a complex beast, with a multitude of different ways of setting things up (which has both pros and cons).
2. The basic configuration really has to be improved to save multiple man-hours that are spent across the Grid trying to debug basic problems.

At the moment, this system is only a prototype. It is intended as an aide to understanding dCache configuration and looking for potential bugs. As always, comments are welcome.

PS Thanks to Steve T for inspiring me to work on this following his graphing glue project.

1 comment:

Brian Bockelman said...

Some more to play with: