Using varnish-2.1.5 SVN On Fri, Apr 29, 2011 at 11:26 AM, Howard Rauscher <[email protected]> wrote:
> My company had an interactive widget posted on the homepage of a very high > traffic media company during the Royal Wedding. We were hosting most of the > widget on Amazon S3, but every 5 seconds we polled our server via JSONP to > get updated stats about the event. > > A couple of weeks ago we realized that JSONP effectively cache busts > varnish. I searched around the internet and found a novel way to use our > varnish server to mitigate this situation. > > Here is an example of our VCL: > https://gist.github.com/f1d91b64acdb3f1d7769 > > At around 5:00am US CST (maybe earlier), about a 1/3 of our api through > varnish returned 503's. We ended up just removing the relevant JSONP > solution and let varnish to be cache busted. Now that the situation has > cooled off a little, I was wondering if I could get some advice on this > config. > > Is this a good solution to the JSONP problem? > > Our setup: > > - 6 EC2 servers (not sure which setup) > - Each server had one varnish and one webapp > - 7188 megs of ram each > - 2 GB allocated to varnish > - ~1500 req/s > - 99.2% hit rate > - And example backend success were ~600/s and backend failures were > ~300/sec > > An example url would be: > /username/streamname.json?jsonp=callback8&items=item1,item2 > > The 503 response would contained text "Guru Meditation:XID: 1518618356". > Not sure what that means though. > > thanks, > Howard >
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