dlm_tcpdump - a simple network sniffing tool for DLM


This is a very basic DLM analysis tool that watches the local network for
DLM packets and prints them on stdout. It works best with GFS but should
copy quite happily with other DLM traffic too.

It's primary use is in identifying heavy DLM users. It will display
the REMOTE locks taken out by processes and identify them by PID and
process name.

NOTE: because it sniffs the network it can only identify locks taken out
on the local system that are mastered on another system. If you don't 
understand what this means then you should probably read 
http://people.redhat.com/ccaulfie/docs/rhdlmbook.pdf

This isn't as much of a restriction as you might think, as it's 
locking traffic that cases the bottleneck mostly anyway, local locking
is VERY fast.

Christine Caulfield, October 2008