Running highly-available WordPress is especially challenging, because WordPress is not by nature Active/Active-aware, and will refuse to run in an environment where database writes are active-active. In this blog post Part 1, we will explore the design considerations for making WordPress highly-available at the database layer. We also cover some other WordPress HA architecture needs, like the need for a shared filesystem.
Global WordPress High Availability Using Tungsten Clustering, Part 1
Cluster Management, Database Administration