Moving one of our eight photoserving farms from hardware Layer7 URL hash balancing (expensive, has limits) to L4 DSR balancing with CARP (cheap and simple) and figuring out how to juggle 18,000 requests/second while we do it.
Built yet some more automated query analysis reporting (with some yummy MySQLProxy)
Added yet another aggregated graph of database queries, broken down by type and cluster
Bunch of cfg mgmt changes (polishing up IO scheduling and filesystem tunings in a 2nd datacenter, more caching of search results)
Review of the higher priority to-dos in the Ops open bug queue (only 155 open! 🙂 )
Finding new capacity ceilings for the image processing, given some recent optimizations)