In a Multi-AZ deployment, Amazon RDS mechanically provisions and maintains a synchronous standby duplicate in a unique Availability Zone. The first DB occasion is synchronously replicated throughout Availability Zones to a standby duplicate to offer knowledge redundancy, eradicate I/O freezes, and decrease latency spikes throughout system backups. Working a DB occasion with excessive availability can improve availability throughout deliberate system upkeep and assist shield your databases towards DB occasion failure and Availability Zone disruption.
Creating Multi-AZ deployment
You possibly can select the choice of choosing a multi-AZ deployment when making a DB occasion or it’s also possible to select the choice of modifying an current db occasion to turn into a multi-AZ DB occasion. The next diagram exhibits the choice the place we’re modifying an current possibility. However the identical possibility can also be accessible throughout the creation of the DB occasion.
How Multi-AZ works
Within the occasion of a deliberate or unplanned outage of your DB occasion, Amazon RDS mechanically switches to a standby duplicate in one other Availability Zone when you have enabled Multi-AZ. The time it takes for the fail over to finish is determined by the database exercise and different circumstances on the time the first DB occasion turned unavailable. Fail over instances are usually 60-120 seconds. Nevertheless, giant transactions or a prolonged restoration course of can enhance fail over time.
Multi-AZ deployments for Oracle, PostgreSQL, MySQL, and MariaDB DB situations use Amazon’s failover know-how. SQL Server DB situations use SQL Server Mirroring.