Category: scaling
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HyperDB Replication Lag Detection
Howdy – Iliya here again. Seems like I am taking over Barry’s blog. Hopefully this will motivate him to blog more. On WordPress.com we have over 218 million tables and perform tens of thousands queries per second. To scale all of this, we shard our 24 million blogs across more than 550 MySQL servers. This…
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Load Balancer Update
A while back, I posted about some testing we were doing of various software load balancers for WordPress.com. We chose to use Pound and have been using it past 2-ish years. We started to run into some issues, however, so we starting looking elsewhere. Some of these problems were: Lack of true configuration reload support…
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Static hostname hashing in Pound
WordPress.com just surpassed her 300th server today. How do we distribute requests to all those servers? We use Pound of course. For those of you not familiar with Pound, it is an open source software load balancer that is easy to setup and maintain, flexible, and fast! In general, we do not stick individual sessions…
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Making Gravatar fast again
As Matt blogged, Automattic recently purchased Gravatar. The first thing we did was move the service onto the WordPress.com infrastructure. Since the application is very different from WordPress.com what this really means is using what we have learned from scaling WordPress.com to increase both speed and reliability of the service, as well as leveraging our…
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Redundancy and power outages
Scott Beale reports that many Web 2.0 websites were affected by today’s power outage at 365 Main in San Francisco. While unfortunate, as a systems guy I have to assume things like this are going to happen. They shouldn’t happen, but they can and they will. At the data center level, there should be multiple…
Barry on WordPress 