Those of you studying the vmstat(8) man page may be wondering what the ’st’ figure is in the CPU column. The manual refers to it as “Time stolen from a virtual machine“. More specifically:
It’s the time the hypervisor scheduled something else to run instead of something within your VM. This might be time for another [...]

Check my post from today on the Rackspace Cloud blog. It covers several tips on planning ahead when writing a web-scale application.

Imagine that you have a cluster with two machines side by side in an active/standby configuration. Let’s say you have your data replicated, and the systems are basically identical except for the IP address and hostname. You can use heartbeat to share an IP address such that if the primary fails, the secondary takes over. [...]