# What Are Full Backup and Incremental Backup?

After an initial full backup, an ECS continues to be backed up incrementally by default.

- The initial full backup covers data on every disk of the ECS. If a 100 GB disk contains 40 GB data, the initial backup consumes 40 GB backup space.
- Subsequent incremental backup backs up data changed since the last backup. If 5 GB data is changed since the last backup, only the 5 GB changed data will be backed up.

VBS allows you to use any backup (no matter it is a full or incremental one) to restore the data of the entire EVS disk. By virtue of this, manual or automatic deletion of a backup will not affect the restoration function.

Suppose EVS disk X has backups A, B, and C (in time sequence) and every backup involves data changes. If backup B is deleted, you can still use backup A or C to restore data.

Parent topic: FAQs