Hi Vineet. I'm not a big fan of multicasts either. Right now I generate ganglia metrics on around 150 nodes. Gmetric is also used to produce a large number of custom metrics in addition to gmond's built in metrics. Multicast packets are sent to every single host machine on a router/subnet. Multicast channels allow you to label the packets but it doesn't result in any kind of network filtering. The solution is UDP unicasts and I am eagerly waiting Ganglia 2.6.0 which implements this feature which for me is essential if I am to stand a chance of convincing our systems people that Ganglia will scale. Please Matt, roll out the unicast feature.
---- Yemi > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Vineet Mokashi > Sent: Tuesday, September 07, 2004 2:39 PM > To: [email protected] > Subject: [Ganglia-general] Multicast issue: High bandwidth usage > > 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. > > > ------------------------------------------------------- > This SF.Net email is sponsored by BEA Weblogic Workshop FREE > Java Enterprise J2EE developer tools! > Get your free copy of BEA WebLogic Workshop 8.1 today. > http://ads.osdn.com/?ad_id=5047&alloc_id=10808&op=click > _______________________________________________ > Ganglia-general mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/ganglia-general >
