Backup and Restoration

Automated backup is an Amazon RDS feature that automatically creates a backup of your database. This backup occurs during a daily user-configurable period of time known as the backup window. Backups created during the backup window are retained for a user-configurable number of days (the backup retention period).

When the backup retention changes to a non-zero value, the first backup occurs immediately. Changing the backup retention period to 0 turns off automatic backups for the DB Instance, and deletes all existing automated backups for the instance.

You can specify the daily backup window for the automated backup when you create or modify your DB Instance. If you don't specify a preferred backup window when you create the DB Instance, Amazon RDS assigns a default 30-minute backup window which is selected at random from a 8-hour block of time per region. The following table lists the time blocks for each Region from which the default backups windows are assigned.

Changes to the backup window take effect immediately. The backup window cannot overlap with the weekly maintenance window for the DB Instance.

	Note
	Automated backups are enabled by default for a new DB Instance.

For more information on working with automated backups, go to Working With Automated Backups.

Point-In-Time Recovery

In addition to the daily automated backup, Amazon RDS archives database change logs. This enables you to recover your database to any point in time during the backup retention period, up to the last five minutes of database usage.

Amazon RDS stores multiple copies of your data, but these copies are stored in a single availability zone for Single-AZ DB Instances. If for any reason a Single-AZ DB Instance is not usable, the DB Instance enters the failed state. In the unlikely event this occurs, you can use point-in-time recovery to restore your database instance to the latest restorable time. For more information on working with point-in-time recovery, go to Restoring a DB Instance to a Specified Time.

	Note
	Multi-AZ deployments store copies of your data in different Availability Zones for greater levels of data durability. For more information on Multi-AZ deployments, see Multi-AZ Deployments.

DB Snapshots are user-initiated backups of a DB Instance. DB Snapshots are retained until they are deleted by the user. For more information on working with DB Snapshots, see Creating a DB Snapshot and Restoring From a DB Snapshot.

Amazon RDS automated backups and DB Snapshots are currently supported for the InnoDB engine only. Use of these features with other MySQL engines, including MyISAM, may lead to unreliable behavior while restoring from backups. Specifically, since storage engines like MyISAM do not support reliable crash recovery, your tables can be corrupted in the event of a crash. For this reason, we encourage you to use the InnoDB storage engine.

If you choose to use MyISAM, you can attempt to manually repair tables that become damaged after a crash using the REPAIR command ((see: http://dev.mysql.com/doc/refman/5.5/en/repair-table.html). However, as noted in the MySQL documentation, there is a good chance that you will not be able to recover all your data.

If you wish to take DB snapshots with MyISAM tables, follow these steps:

Finally, if you would like to convert existing MyISAM tables to InnoDB tables, you can use alter table command (for example, alter table TABLE_NAME engine=innodb;).