In this three-part blog series, we will explain the details and
functionality of a High Availability (HA) framework for MySQL
hosting using MySQL semisynchronous replication and the
Corosync plus Pacemaker
stack. In Part I, we’ll walk you through the basics of High
Availability, the components of an HA framework, and then
introduce you to the HA framework for MySQL.
What is High Availability?
The availability of a computer system is the percentage of time
its services are up during a period of time. It’s generally
expressed as a series of 9′s. For example, the table below shows
availability and the corresponding downtime measured over one