Choosing the right backup methodology is one of the most consequential decisions in backup architecture design. The choice between full, incremental, differential, and synthetic full backup directly affects backup window duration, storage consumption, restore complexity, and impact on production system performance.
Full backups capture every byte of protected data regardless of when it last changed. They produce self-contained recovery points that can be restored without reference to any other backup — making recovery straightforward and fast. The drawback is that full backups consume the most storage and take the longest to complete.
Incremental backups capture only data changed since the previous backup. Backup windows shrink dramatically and storage consumption is far lower. Organizations that have deployed differential vs incremental backup as their backup target typically find that the appliance's deduplication engine reduces the effective storage footprint significantly across backup chains.
Differential backups capture all data changed since the last full backup. Recovery requires only two files: the last full backup and the most recent differential. This simplicity makes differentials attractive when restore speed is prioritized.
Synthetic full backups represent the modern synthesis. Rather than transmitting a full backup from source systems each week, synthetic fulls consolidate the existing base full and subsequent incrementals into a new virtual full backup without reading source data again. This eliminates the source-system performance impact of weekly full backup jobs.
Most enterprise backup platforms support incremental-forever strategies: a single initial full backup followed by perpetual incrementals, with synthetic fulls created periodically on the backup target. Retention policies expire older incrementals automatically once synthetic fulls are confirmed healthy.
