In summary: more site improvements. Fun stuff.
All our images (icons and userpics) are now being served by Speedera. Wherever you are in the world, the closest Speedera server will service your request. They have tons of bandwidth and tons of servers. And it means we don't have to manage those machines anymore.
In other news, we've put live some new database connection code which dramatically reduces the number of open connections to our databases. One database in particular has been getting hard this past week and has been the bottleneck for the rest of the site (all available web processes were waiting to connect to that one overloaded db). Anyway, that should be fixed now.
The real key to killer performance though is making sure we never block on resources, be they db connections, disk seeks (db), or application locks. Like I said in the last post, there's only one killer query left (for the friends page) that still makes web nodes require the database. We're still working on removing that. Then nearly all data access will be though lockless memcached.
A lot of people asked after my last post if we'd be selling extra userpics. The answer is yes. We've actually had that code ready (for the billing/expiring) for nearly 6 months... we've just been waiting on disk space. We still haven't heard an ETA for when our NetApp (lots of disk space) arrives, but it was supposed to be before Friday, so we'll see. With luck, we'll have that online soon (I'd like this weekend) and then we can flip the switch and start selling more userpics.