----- Original Message ----- From: "Steven Wagner" <[EMAIL PROTECTED]>
> Hey, I wonder what would happen if someone specified a non-multicast IP > (running gmond, of course) as the target multicast network... anyone ever > try that? Even if this worked, only the "target" monitoring core would > have all the data (helloooooo, central point of failure), but it seems to > meet your requirements. Or someone could write an "aggregate update" mod > to the monitoring core that requires it to meet a minimum buffer threshold > before sending updates. Or perhaps there's just one or two misbehaving > metrics (run a couple of the monitoring cores on a separate multicast IP in > debug mode and see what metrics pop up the most often...). > I think whats mentioned above and the ability to toggle gmond so that it can listen back to its own reports either internally or from the 'target' gmond that would relay the data back, would be a good approach. Better to go internally though ;) Also I agree with the usefulness of having a second administrative interface, although at the expensive of using more ports on a switch. But the other issue is not so much the switch having to deal with lots of packets, which as you point out is a low percentage, but that the receiving computers kernel and networking code also have to deal with the packets coming in. That in turn could still degrade a machines ability to process nfs and other activity. Or maybe it isn't all that substantial. I'd rather err on the side of having a cleaner/simpler running network though! I'm pretty sure the catalyst switches can be set to do multicast more effeciently by setting 'ip cgmp' on them, though I haven't confirmed this. With 'ip cgmp' set on, machines can join and leave multicast channels as they please and the switch will only direct packets to those machines that need to listen to them. Normally though, the switch is literally just broadcasting out each and every multicast ip packet to every machine on the lan/vlan. I don't have direct access to the catalyst switches at work and I haven't gotten the admin in charge to make the change. So in this way if the ganglia community just had a quick html page with confirmed tips on switch configuration it would be a big help.
