# Differences Between EVS Disk Backup and EVS Snapshot

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

Table 1 Differences between backups and snapshots
Item | Storage Solution | Data Synchronization | DR Range | Service Recovery
--- | --- | --- | --- | ---

Backup

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

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

A backup and its source 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 excellent data reliability.

Snapshot

Snapshot data is stored with disk data.

NOTE:

Creating a backup requires a certain amount of time because data needs to be transferred. Therefore, creating or rolling back a snapshot consumes less time than creating a backup.

A snapshot is the state of a disk at a specific point in time. If a disk is deleted, all the snapshots created for this disk will also be deleted. If you have reinstalled or changed the server OS, snapshots of the system disk are automatically deleted. Snapshots of the data disks can be used as usual.

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

You can use a snapshot to roll back its original disk or create a disk for data restoration and service recovery.

Parent topic: Overview