On 15/10/12 06:58, David Gerard wrote: > On 14 October 2012 16:34, Platonides <[email protected]> wrote: >> On 13/10/12 00:22, David Gerard wrote: > >>> Apache connections are really pretty damn cheap these days. Is >>> KeepAlive actually a good or bad thing for MediaWiki? > >> The apache docs say: >>> In some cases this has been shown to result in an almost 50% speedup >>> in latency times for HTML documents with many images. >> -- http://httpd.apache.org/docs/2.4/mod/core.html#KeepAlive >> I'd keep it on, but with a small KeepAliveTimeout > > > Mmm. Say YMMV. In our case the constraint is memory (we're fine for > CPU and bandwidth), and our next Reddit-dotting not knocking us over > again. Here's a graph, guess when I switched off KeepAlive: > http://i49.tinypic.com/2jczzht.jpg
That's processes, not memory. I would think that the effect on memory would not be so large. Disabling keep-alive should be counted as a fairly desperate measure given the large impact on end user latencies. I haven't ever had to run a high-traffic wiki apart from Wikipedia, but if one of my little VPS wikis got slashdotted, I think the first thing I would do is install Squid. Squid needs a tiny amount of memory per connection, maybe 1KB. You can let Squid keep the client connections open for a few minutes, but disable keepalive on Apache. That way you minimise the number of memory-guzzling Apache processes with minimal user impact. This is one of the reasons we use Squid at Wikimedia. I think it should be possible to run both Apache and Squid on a VPS with a few hundred MB of RAM. Just have Squid on port 80 and Apache on some private firewalled port. If you have any RAM left over, you can allocate it to Squid for caching, and unless your site is enormous, you can give it whatever disk cache it needs to serve the whole site without ever contacting the backend. The MW file cache might be fast, but Squid is always going to be faster. -- Tim Starling _______________________________________________ MediaWiki-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/mediawiki-l
