Introduction to high availability

Introduction to high availability

High availability systems seek to minimize the following issues:

  1. System downtime: Occurs when a user-facing service is unavailable beyond a specified maximum amount of time.

  2. Data loss: Accidental deletion or destruction of data.

Most high availability systems guarantee protection against system downtime and data loss only in the event of a single failure. However, they are also expected to protect against cascading failures, where a single failure deteriorates into a series of consequential failures. Many service providers guarantee a Service Level Agreement (SLA) including uptime percentage of computing service, which is calculated based on the available time and system downtime excluding planned outage time.

Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.