Paulo and me (kim0) have been working on testing a caching setup for the wiki. A test migration to Moin 1.5 is complete, squid is now configured as a reverse caching proxy. We've done some stress tests on the current setup. Attached are some extracted results that (I think) are of interest. Mainly the number of requests served per second, and the average time for serving a request. Also, paulo pointed that caching differs per file type, the tests have been done on three different file types (html, png image, and css)
1- All connections were initiated from proxy1
2- Proxy2 had squid caching turned on
3- Testing for html/png/css done, sweeping the number of concurrent connections
4- Turn off squid caching on proxy2
5- Testing for html/png/css done, sweeping the number of concurrent connections again
1- Serving PNG is 10X faster than html
2- Serving CSS is 10X faster than PNG!
3- Serving html is really the bottleneck. Unfortunately, Moin developers acknowledged current version (
1.5) is not cache friendly. Work for making 1.6 cache friendly is undergoing
4- Using squid currently only seems to double our PNG serving rate, nothing else
5- The application server hits swapping (about 0.5GB) at full load (~300 concurrent connections), for some reason the requests/second served is still high!! (Is our cache disks that fast)
6- The test did not stress the server bad enough to run out of swap space, not sure if this is needed though!
I can send the full results date if anyone is interested.