On 29 October 2012 23:56, Dave Humphrey <[email protected]> wrote: > As a rough guess at what to set MaxClients to use "top" and look at the > difference between the RES and SHR columns of all httpd processes. I > believe this is roughly the amount of non-shared memory each of the child > Apache processes are using (for example, I'm averaging 10 MB per process). > Take the maximum amount of RAM you want Apache to use and divide it by this > memory to get a rough number for MaxClients. You can monitor memory usage > and adjust this as needed or through load testing.
I just set MaxClients 50 (on the basis of fat apache2 processes having ~50MB discrepancy between RES and SHR). Let's see what happens. > Of course, this is a solution to the usage of swap and not the actual issue > you are having. I would continue to look at what is causing the surge in > requests. Is it a DoS of some sort (either accidental or on purpose) or is > some part of the server stalling which is causing requests to pile up and > overflow? For example, if the database is having an issue (a bunch of long > queries) then all Apache requests will start piling up until you hit swap > or the database issue resolves itself. I see that in busy times, the CPU usage goes way up and a chunk of it is MySQL. I could be wrong, but this suggests to me complex requests to MediaWiki (e.g. logged in editors right-clicking diffs on an obscure page). I should probably profile MediaWiki, given we have a pile of custom extensions. > Along these lines I would suggest some sort of monitoring/logging service > like Zabbix or Nagois (to name just two, there are many similar options to > choose from). This helps you on two fronts: 1) Logging of Parameters and 2) I live on our Munin graphs :-) - d. _______________________________________________ MediaWiki-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/mediawiki-l
