This issue has been addressed earlier, but no fool-proof solution was suggested. Now that I have been monitoring our 32-node Beowulf, running RHEL-AS with 2.4.20-20.9smp kernel, the problem has started to look grave.
Upto 60% of the packets on each node can be attributed to gmond and the inter-process communication is getting affected due to this. Turning on 'deaf' mode does not help, since gmetad is unable connect to 8649 to get any data from the gmond daemons. As a probably workaround, I (painfully) configured gmond with a separate multicast channel for each node, say 239.2.11.40-72, and removed all trusted_host entries (but for the login node, which runs gmetad). This solves a part of the problem - every node's gmond communicating with every other node to probe data. The bandwidth consumption has decreased significantly. The broken link with this set-up is that gmetad is unable to query data from any node except the one running on the default multi-cast channel. All the gmond daemons use the default XML port : 8649. Has anyone tried something like this before? How can we get gmetad to query multiple multicast channels? On top of all this, the latest snapshot of ganglia-2.6.0 fails to build. Regards, Vineet (Newbie Linux Administrator) ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
