High availability (HA) is an architectural design approach that keeps a system operational continuously by eliminating single points of failure — ensuring that if any individual component (a web server, database server, or network link) fails, the system remains accessible without manual intervention. For WordPress, a high-availability configuration typically involves multiple web server nodes sitting behind a load balancer (distributing incoming requests across healthy nodes), a replicated database layer (MySQL primary-replica or Aurora multi-AZ), persistent shared file storage accessible by all web nodes (via NFS or S3-backed media storage), and a centralized Redis or Memcached object cache. A standard single-server WordPress install has a single point of failure: if the server reboots or crashes, the site goes down until the server recovers. Enterprise WordPress platforms including WordPress VIP, WP Engine Enterprise, and Pantheon provide high-availability architectures by default, with SLAs typically guaranteeing 99.95% or higher uptime.
Glossary entry
