Incremental backups of MySQL, specifically for the InnoDB engine, are taken by copying modified pages from the previous backup.
The brute force method takes backups by scanning every page in tablespace file in the server data directory is an expensive operation. The time required for incremental backups increases as the data-dir size increases.
To solve this problem, Percona Server for MySQL introduced a “Changed Page Tracking” feature in 5.6 that enables Percona XtraBackup (PXB) to copy only the modified pages required for incremental backups. See the Percona XtraBackup Documentation for more information. …[Read more]