On Fri, 7 Jan 2011 23:10:06 -0500, Jesse Becker <haw...@gmail.com> wrote: > > I think that it's fine to set this to a non-zero value, but I wonder > if 30 seconds is too high. I did a quick set of checking on the > actual packets that are sent--and specifically the metadata packets. > I haven't been able to really delve into the code to figure exactly > what's going on (this part of the code is't terribly transparent to > me), but I *think* that they are really large--on the order of several > KB when fully assembled, as compared to less than 100-120 bytes for a > typical metric packet . I think that size will increase with the > number of metrics stored, since each one must be described in full XML > each time.
I think sending couple kBytes every 30 seconds is not that bad. Even if you have a 1000 hosts and a 5 kB payload we are talking only about 10 Mbytes every minute. With speeds of networks today I'd consider that to be noise. > On a large cluster, with lots of metrics per host, I can see problems > if the metadata packets are sent too frequently. I have hosts that > send well over 300 metrics (lots of CPU cores makes for lots of > metrics...). Each of these need to be described in the metadata > packets. > > So I think that setting a non-zero default is fine. But think that > something like 300 or 600 seconds would be preferable. I think we should shoot for a default that works best for most people. 300 or 600 seconds is too long since during those 300-600 seconds I'm "flying blind". This may not matter as much in HPC settings but it matters a lot to web startups. Secondly most networks are not very big so the overhead will be minimal. In closing I'd say let's go with 30 seconds. We can add a comment above the value that says something like - If you are in a large network you may consider making the value higher as every hosts sends metadata payload of few kilobytes every interval. Vladimir ------------------------------------------------------------------------------ Gaining the trust of online customers is vital for the success of any company that requires sensitive data to be transmitted over the Web. Learn how to best implement a security strategy that keeps consumers' information secure and instills the confidence they need to proceed with transactions. http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ Ganglia-developers mailing list Ganglia-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ganglia-developers
