Updated on 2024-07-04 GMT+08:00

Creating an EVS Snapshot

Scenarios

You can create EVS snapshots to save disk data at specific time points. Before you perform any critical operation, such as a data rollback, software upgrade, or data migration, you are advised to create snapshots to back up data. This ensures that your data is not affected even if an exception occurred during the operation.

During the snapshot creation, disk I/Os are affected, so you may experience slow reads or writes at some points. It is recommended that you create snapshots at off-peak hours.

Prerequisites

Snapshots can only be created for Available or In-use disks.

Notes and Constraints

  • Snapshots can be created for both system disks and data disks.
  • Snapshots of encrypted disks are stored encrypted, and those of non-encrypted disks are stored non-encrypted.

Snapshot function in OBT (view supported regions)

  • You can manually create a maximum of seven snapshots for a disk.
  • The enterprise project of a snapshot is the same as that of the snapshot's source disk.

Snapshot function in commercial use (view supported regions)

  • You can manually create a maximum of 256 standard snapshots for a disk, of which up to seven can have Instant Snapshot Restore enabled.
  • You can create one standard snapshot for a disk at a time. You can only create the next standard snapshot for the same disk after the previous snapshot has been created.
  • Standard snapshots cannot be created for the disks in edge AZs. For details about the differences between edge AZs and general AZs, see the .
  • When standard snapshots are created for Common I/O and High I/O disks, Instant Snapshot Restore cannot be enabled.
  • It usually takes several minutes to create a standard snapshot. The time required varies depending on the amounts of data written to the disk. The larger the data volume, the longer the time required. The initial standard snapshot usually takes more time because data of the entire disk is backed up. Subsequent standard snapshots are quicker, but the time required is still determined by the amounts of changed data compared with each last snapshot. The more the changed data, the longer the time required.
  • If the data on a disk is rolled back from a snapshot, the next standard snapshot created for this disk will be a full snapshot.
  • During the creation of a standard snapshot, any incremental data written to the disk will not be backed up to the snapshot created.
  • During the creation of a standard snapshot, deleting the snapshot's source disk does not affect the creation of the snapshot.

Snapshot Function in OBT

Snapshot Function in Commercial Use