Wikimedia Platform Engineering/Site performance and architecture

Rationale
Many small architectural changes and improvements are being done all of the time without a lot of fanfare. This is a general activity area where we communicate changes made along these lines.

April-June 2013

 * JobQueue improvements
 * Eqiad migration wrapup
 * Migrate fenari to tin.eqiad.wmnet
 * Migration to Ceph - still running sync scripts, possible split-brain issues with memcache
 * Migrate hume to terbium.eqiad.wmnet

July-September 2013
punt

October-December 2013

 * New deployment system (replacing scap)
 * Caching improvements
 * - Rewrite jobs-loop.sh in a proper programming language
 * - Redirect to canonical encoding
 * - When a commons image is updated, update the pages that use it
 * - Include version in thumbnail URL
 * - Queue refreshLinks jobs on template deletion
 * - Separate Cache-Control header for proxy and client
 * - Enable importing across all Wikimedia projects
 * - resetUserTokens.php not usable on large wikis

January-March 2014

 * HipHop
 * Implement Lua extension
 * Develop prodution configuration