Simon Willison’s Weblog

5 items tagged “haproxy”



How Balanced does Database Migrations with Zero-Downtime. I’m fascinated by the idea of “pausing” traffic during a blocking site maintenance activity (like a database migration) and then un-pausing when the operation is complete—so end clients just see some of their requests taking a few seconds longer than expected. I first saw this trick described by Braintree. Balanced wrote about a neat way of doing this just using HAproxy, which lets you live reconfigure the maxconns to your backend down to zero (causing traffic to be queued up) and then bring the setting back up again a few seconds later to un-pause those requests. # 7th November 2017, 11:36 am


How We Made GitHub Fast. Detailed overview of the new GitHub architecture. It’s a lot more complicated than I would have expected—lots of moving parts are involved in ensuring they can scale horizontally when they need to. Interesting components include nginx, Unicorn, Rails, DRBD, HAProxy, Redis, Erlang, memcached, SSH, git and a bunch of interesting new open source projects produced by the GitHub team such as BERT/Ernie and ProxyMachine. # 21st October 2009, 9:14 pm

Ravelry. Tim Bray interviews Casey Forbes, the single engineer behind Ravelry, the knitting community that serves 10 million Rails requests a day using just seven physical servers, MySQL, Sphinx, memcached, nginx, haproxy, passenger and Tokyo Cabinet. # 3rd September 2009, 6:50 pm

Load Balancing in Amazon EC2 with HAProxy. Solid tutorial introduction to HAProxy. # 5th February 2009, 11:12 pm