Snapshots are read-only, point-in-time copies of data in a volume, volume group, virtual machine, or file system. Snapshots are commonly used to create copies of databases for use with new applications, or to develop and test existing databases applications. The PowerStore T can take snapshots of file systems (SMB and NFS) and block-based systems. In our MySQL tests, we took block snapshots of the database volumes while the database was not running.
The PowerStore administrator can create write-ordered-consistent or application-consistent snapshots. With write-ordered snapshots, the array creates a copy of the volumes in which all writes are order-consistent, ensuring that the database or application can be recovered or repurposed. With write-consistent snapshots, no database or application recovery is required, although with some databases it is recommended to place the database in hot backup mode.
You can also specify a thin clone when creating a copy of the database. Both the original source database and the thin clone of the database can be updated and modified. Even if the original source database is removed, the thin clone is unaffected and the business can continue using the cloned database. With thin clones, the business can establish hierarchical snapshots to preserve data over time and in different states.
You can use snapshots and thin clones to refresh a storage resource. The process starts with removing the existing data. A good tip is to take a snapshot of the data or database before removing it as a backup. If the business needs to recover the original data, this can be accomplished using the backup snapshot. The refresh completes when all data has been copied. Refreshing a database enables activities such as incremental testing or destructive tests and is useful in many other scenarios. Both snapshots and thin clones benefit from data reduction, which saves substantial space on PowerStore systems.
Note: In this study, the MySQL database was not running when the snapshot was taken. If the database is down, there is no need to complete steps 1 – 4 below.
You can create point-in-time recovery-(PITR) consistent backups by completing the following steps:
Integrate these steps in the shell script for your daily and weekly backup solutions. PowerStore T Snapshot technology backs up terabytes and petabytes in a matter of seconds. This feature is helpful for the MySQL ecosystem where the traditional approach (logical or hot backup) of creating backups takes longer and uses more network and disk bandwidth.
The following section describes how to create the production database snapshot using PowerStore T snapshot technology.