Pushing dynamic content via AJAX and caching the much larger part of the page that isn't dynamic is a great tip -- much better than caching fragments. I will now steal it and appear smart by telling others. :-P
Varnish is most definitely a huge win. It can be somewhat of a pain to install if you're not using Chef or something, though. Here's some helpful info I compiled that might come in handy for first-timers:<p>Installing Varnish with nginx, Passenger, and Monit on Ubuntu 8.10 intrepid:<p><a href="http://trevorturk.com/2009/10/22/installing-varnish-with-nginx-passenger-and-monit-on-ubuntu-8-10-intrepid/" rel="nofollow">http://trevorturk.com/2009/10/22/installing-varnish-with-ngi...</a><p>It's a bit out of date now, but basically still applicable.<p>Also, here are some packages for Sprinkle, which is an alternative to Chef that I like:<p><a href="http://github.com/trevorturk/sprinkle-packages" rel="nofollow">http://github.com/trevorturk/sprinkle-packages</a><p>Varnish is not installed by the default example, but look in packages/varnish.rb and you'll be able to sort it out.<p>Go go gadget Varnish!
Nice choice. This post about Varnish architecture is one of my favorites: <a href="http://www.varnish-cache.org/trac/wiki/ArchitectNotes" rel="nofollow">http://www.varnish-cache.org/trac/wiki/ArchitectNotes</a>
Slightly off-topic: Varnish has some really beautiful C code. It's so good you can get the source code in book form. Check out:
<a href="http://ing.dk/modules/xphoto/cache/40/31740_460_400.jpg" rel="nofollow">http://ing.dk/modules/xphoto/cache/40/31740_460_400.jpg</a>
<a href="http://phk.freebsd.dk/misc/_book2.pdf" rel="nofollow">http://phk.freebsd.dk/misc/_book2.pdf</a> ;)
Happy to see varnish get so much airtime recently, it's a great piece of software and I would not be able to run my service at the current budget without it. If you are not a varnish user yet and you have a high volume site, go check it out, and save yourself some big $ by better utilizing the servers that you already have.
Varnish is very attractive, and it is something that my organization is beginning to look at.<p>But, this appears to be a new blog from Posterous, with this submission being it's first post, and it comes to HN just after Posterous had some, well potentially negative press about their traffic.<p>Am I off base in asserting that this blog post is a marketing play? And if this isn't their first blog post, please let me know of my grave error (and down-vote me accordingly)<p>Edit and follow-up: This blog has been around for a while, so I guess I'll sit back and relax. However, I'll still stand behind the marketing assertion.
Their description of Lacquer sounds problematic to me.<p>The usual failure case for this is that a cache node goes down for awhile, misses some invalidation messages, then comes up and starts serving (stale) traffic again.<p>This case isn't so bad if you keep your TTL low, and have cheap page revalidation.
Interesting, we also added a Varnish based cache layer and also got a dramatic performance boost. The connections to the backend dropped to 50%, taking off a lot load.<p>I am currently going through your VCL to take some ideas for improvement. Thanks for posting that.