I don't know about 20-50% increase but some areas did increase while others decreased. For example, under 3.0.x if you were only monitoring the built in metrics, the overhead in both XDR and XML was very low. The reason why is because much of the data was hard coded in every instance of gmond. Since every gmond knew what metric 2 was (for example), there was no need for any gmond to provide any other gmond with any further information. However, if you used gmetric, then for every metric gathered by gmetric, a full description of the metric had to be passed between gmonds along with every value gathered. This increased the XDR packet size. With the introduction of the metric modules in ganglia 3.1.x, the hard coded metric information didn't work anymore because metric modules where dynamically loadable. This meant that each gmond needed to communicate its metric descriptions with every other gmond. But in order to decrease the amount of meta data that was being passed around, the XDR packets where split into meta data packets and value packets. Meta data packets are only sent when needed rather than with every value gathered. When using multicast, the meta data packets are only sent when gmond is first started or when requested by another gmond which may have joined the channel later. In unicast mode, the meta data packets are sent at a given interval that is specified by the gmond configuration. This 3.1.x scheme should have the effect of decreasing the XDR traffic in comparison to 3.0.x when using 3.1.1 modules vs. 3.0.x gmetric. But there will be an increase over 3.0.x when no gmetrics are used. With regards to the XML traffic, this has increased due to the fact that more information such as grouping and titles have been included as extra data. This additional information helps to enhance the metric presentation in the web front end. But the increase in the size of the XML should only slightly impact the gmetad server only. But as of 3.1.1, there is an option to turn off all extra data which basically drops the size of the XML back to the same level as 3.0.x.
Brad >>> On 10/16/2008 at 12:27 PM, in message <[EMAIL PROTECTED]>, john allspaw <[EMAIL PROTECTED]> wrote: > I don't want to reply there, but... > > reports in that thread of gmond creating 20-50% overhead? I can't imagine > that at all, and since the discussion devolved into "I hate XML", it doesn't > sound like such a productive discussion. How could it be possible for gmond > to take that much of a hit? Maybe it's time I grabbed some stats from one of > our database machine which has gazillions of MySQL gmetrics.... > > -j > > > ----- Original Message ---- >> From: Bernard Li <[EMAIL PROTECTED]> >> To: ganglia-developers <ganglia-developers@lists.sourceforge.net> >> Sent: Tuesday, September 23, 2008 10:43:59 AM >> Subject: [Ganglia-developers] Ganglia discussion in Beowulf mailing-list >> >> Howdy! >> >> There is a discussion going on in Beowulf mailing-list which touches >> on Ganglia -- some of you may find it interesting: >> >> http://www.beowulf.org/pipermail/beowulf/2008-September/thread.html#23239 >> >> Cheers, >> >> Bernard >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >> Build the coolest Linux based applications with Moblin SDK & win great prizes >> Grand prize is a trip for two to an Open Source event anywhere in the world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> _______________________________________________ >> Ganglia-developers mailing list >> Ganglia-developers@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/ganglia-developers > > > > > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Ganglia-developers mailing list > Ganglia-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/ganglia-developers ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Ganglia-developers mailing list Ganglia-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ganglia-developers
