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Databases & SQL vocabulary · Backup, Replication and Scaling

High availability

Meaning in databases & SQL, with examples

nounCommon term

In databases & SQL, high availability means: Designing a database system so that it keeps working with very little downtime, even if a server, disk or data center fails.

In Turkish: yüksek erişilebilirlik, yüksek kullanılabilirlik

How it is used

Shortened to HA, as in 'an HA setup' or 'HA cluster'. It is built with replication, standby servers and automatic failover, and often measured in 'nines': 99.99% availability allows under an hour of downtime per year. HA does not replace backups.

Example sentences

  1. For high availability we run a primary and two standbys in different zones.

  2. The contract requires high availability of 99.95% for the payments database.

Common collocations

  • high availability cluster
  • HA setup
  • design for high availability
  • 99.99% uptime
  • failoverSwitching work from a failed primary database server to a standby or replica so that the application can keep running.
  • replicationKeeping copies of the same database on several servers by sending every change from one server to the others, for safety and to share the load.
  • read replicaA copy of a database that receives changes from the main server and is used only for read queries, taking load off the primary.
  • backupA copy of a database saved at a certain moment so that the data can be brought back after a failure, a mistake or an attack.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Backup, Replication and Scaling

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