This guide can be used to recover from a snapshot for a MySQL instance. Recovery can be done for the original system a snapshot was taken from or for copying the MySQL instance to a new location.
This knowledge article covers the creation of volume snapshots for the entire MySQL Instance.
To move an individual database/schema using volume snapshots see Moving Individual Databases Between Instances Using Volume Snapshots.
The concepts and instructions explained here can be applied to both MySQL and MariaDB.
The method for recovering a MySQL system from storage snapshots will vary in the following scenarios:
- The volume snapshot is created on a system using the Recovering MySQL From FlashArray Volume Snapshots or the default layout is preserved but in a different location.
- The data , transaction and binary log file system locations are all separate.
- The files for a specific database/schema are on a separate volume.
The recovery method for application consistency is the same as crash consistency. The difference between the two approaches is how consistency is guaranteed.
The MySQL option file should attempt to be as similar to the variables used when the storage snapshot was taken. The most important variable to ensure remains the same is innodb_page_size. If the storage snapshot was taken without this property being set then the default value is 16K. In the event that innodb_page_size is different or has changed then it must be set back to the originating value.
If innodb_log_files_in_group or innodb_log_file_size has changed since the snapshot was taken then post volume recovery and pre startup the log files should be deleted. Log files are recreated on startup if they are not found.