Introduction to MySQL-EBS Concepts

About Manager for MySQL

The Manager for MySQL interface has been designed to hide the low level complexities of managing distributed DB systems in order to provide a simple and intuitive interface. Despite its simplicity, there are still different paths that users can take in trying to resolve the various situations that might arise during the lifetime of the DB system. Not all of these possible resolution choices are always appropriate or even valid. This runbook is designed to guide Manager for MySQL operators in taking decisions that follow the best practices when facing the most typical situations.

EBS Snapshots and Volumes

One of the key concepts to understand about the MySQL-EBS Database setup is that backups of the MySQL DB are saved as EBS snapshots.  EBS volumes are created from a snapshot and are attached to a master/slave instance.  When a MySQL server is terminated, the EBS volume is automatically detached and deleted.   Therefore, all DB restorations are done using snapshots.  Whereas volumes are not persistent, snapshots can be archived and  help protect your data from being lost.  Snapshots also make it easy to launch servers and populate the databases since the template will use the most recently saved snapshot (regardless of whether it's a master/slave) to restore a MySQL database.  If you are setting up a MySQL-EBS deployment for the first time, a few extra steps are required in order to create the first snapshot.  Once you have a snapshot, you can launch and deploy MySQL DB servers in a single step.  

NOTE: A new snapshot will automatically be created once a new master/slave DB is launched or when a Slave-DB is promoted to master.

What are the defaults?  How do I modify them?

• The last 60 EBS snapshots of the Master-DB and the last 60 EBS snapshots of the Slave-DB are saved.  Older snapshots are deleted.
  
  • To change the default, modify the DB_BACKUP_KEEP_LAST input variable at the deployment level.
• Snapshots of the Master-DB are taken once every 4 hours.  You must wait for a snapshot to be 100% complete before it can be used when launching a new DB server.
  
  • To change the default, modify the DB_BACKUP_MASTER_FREQ input variable at the deployment level.
• Snapshots of the Slave-DB are taken once every hour.  You must wait for a snapshot to be 100% complete before it can be used when launching a new DB server.
  • To change the default, modify the DB_BACKUP_SLAVE_FREQ input variable at the deployment level.