# What Are the Differences Between Backup and Snapshot?

Both backup and snapshot provide data redundancy for EVS disks to improve data reliability. Table 1 lists the differences between them.

Table 1 Differences between backup and snapshot
Technology | Saved In | Synchronization | DR Range | Service Recovery
--- | --- | --- | --- | ---

Backup

Backup data is stored in OBS, instead of EVS disks. This realizes data restoration upon EVS disk data loss or corruption.

A backup is the data copy of an EVS disk at a given point in time. CSBS provides automatic backup by configuring backup policies. Deleting an EVS disk will not clear its backups.

A backup and its source EVS disk reside in the same AZ.

Data can be recovered and services can be restored by restoring the backup data to original disks or creating new disks from backups, ensuring superb data reliability.

Snapshot

Snapshot data is stored with EVS disk data.

NOTE:

Creation of and rollback to snapshots are faster than creation of and restoration from backups, because the latter requires data migration that consumes extra time.

A snapshot is the state of an EVS disk at a specific point in time. When you delete an EVS disk, the snapshots of the EVS disk are also deleted.

A snapshot and its source EVS disk reside in the same AZ.

Data can be recovered and services can be restored by rolling back the snapshot data to original disks or creating new disks from snapshots.

Parent topic: About Concepts