Incremental backup is a data protection method that captures only the data blocks or files changed since the last backup of any type. This approach minimizes storage consumption and reduces network bandwidth usage during the backup window by avoiding redundant data transfers.
The system identifies changes using metadata or specialized tracking mechanisms like Changed Block Tracking (CBT). During execution, the software compares the current state of the source with the last successful snapshot and transfers only the unique differences to the storage repository.
This method offers the fastest backup speeds, but recovery is more complex than with full or differential backups. To restore data, the system must process the last full backup and then sequentially apply every incremental update in the chain. A single corrupted file in this sequence can compromise the entire restore process.
Practical Scenario
Incremental backups are essential for meeting strict Recovery Point Objectives (RPO). For a 10 TB production database, a daily incremental might involve only 200 GB of modified data. This allows organizations to run backup jobs every hour without significant performance overhead or storage exhaustion.