It's neat to see these results! A few comments:
I don't see anywhere where variables such as the file size, request
size, HTTP pipelining, etc. are taken into account. Optimally, the
test would have cases that exercise points along all these
dimensions. E.g. a load test of serving an empty file would help us
understand what the absolute best case performance is within the
constraints the current systems.
The other thing that'd be useful to have is a well-defined capacity
goal that helps everyone understand where things ought to be. For a
straw-man example, let's say 20 home page loads/second, including all
associated image/CSS/JS files, by logged-in users. I don't know what
the actual needs are, but a look at the web logs during the FC6
release should help.
From what's mentioned below, I also didn't quite understand whether
squid was sitting in front of apache serving straight HTML/PNG/CSS,
or whether it was moinmoin that contained all the content. Hopefully
that's just something I missed in an earlier message.
My current favorite treatise on optimizing overall web performance -
Hope this helps,
On Dec 23, 2006, at 3:19 PM, Ahmed Kamal wrote:
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
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
4- Turn off squid caching on proxy2
5- Testing for html/png/css done, sweeping the number of concurrent
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,
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.
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