Automated backups with unsupported MySQL storage engines

For the MySQL DB engine, automated backups are only supported for the InnoDB storage engine. Using these features with other MySQL storage engines, including MyISAM, can lead to unreliable behavior when you're restoring from backups. Specifically, since storage engines like MyISAM don't 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.

• To convert existing MyISAM tables to InnoDB tables, you can use the ALTER TABLE command, for example: ALTER TABLE table_name ENGINE=innodb, ALGORITHM=COPY;

• If you choose to use MyISAM, you can attempt to manually repair tables that become damaged after a crash by using the REPAIR command. For more information, see REPAIR TABLE statement in the MySQL documentation. However, as noted in the MySQL documentation, there is a good chance that you might not be able to recover all your data.

• If you want to take a snapshot of your MyISAM tables before restoring, follow these steps:

  1. Stop all activity to your MyISAM tables (that is, close all sessions).

     You can close all sessions by calling the mysql.rds_kill command for each process that is returned from the SHOW FULL PROCESSLIST command.

  2. Lock and flush each of your MyISAM tables. For example, the following commands lock and flush two tables named myisam_table1 and myisam_table2:

     mysql> FLUSH TABLES myisam_table, myisam_table2 WITH READ LOCK;

  3. Create a snapshot of your DB instance or Multi-AZ DB cluster. When the snapshot has completed, release the locks and resume activity on the MyISAM tables. You can release the locks on your tables using the following command:

     mysql> UNLOCK TABLES;

  These steps force MyISAM to flush data stored in memory to disk, which ensures a clean start when you restore from a DB snapshot. For more information on creating a DB snapshot, see Creating a DB snapshot for a Single-AZ DB instance for Amazon RDS.