What is Snapshot?

A snapshot is a point-in-time capture of data status in a volume. Before you perform a business-sensitive operation, you can schedule snapshot creation at specified time points to record the state of the system volume or data volume of a VM instance. This allows rollback in case of breakdowns. If you want to backup data for a long term, you can use Backup Service.

Snapshot Category

Snapshots can be classified into the following two categories:
  • Manual snapshot: snapshots that are manually created for root volumes or data volumes.
  • Auto snapshot: snapshots that are automatically created at a scheduled time interval or in specific scenarios.
    • To create auto snapshots for a resource at a scheduled time interval, you need to create a scheduled snapshotting policy for the resource. This way, the system creates snapshots at scheduled time points for the resource.
    • The system may create an auto snapshot in the following scenarios:
      • Root volume capacity expansion
      • Data volume capacity expansion
      • VM reset
      • Snapshot rollback
        Note:
        • By default, the system does not create a snapshot in case of snapshot rollback.
        • You can enable or disable one-time snapshot-creation in case of snapshot rollback on the Global Setting page.

          Choose Setting > Platform Setting > Global Setting > Advanced > Resource Center > Resource Pool > Snapshot. Turn on or off the Auto Create Volume Snapshot switch based on your business needs.

      • Image creation of root volume or data volume on Ceph primary storage

Snapshot View

ZStack Cloud provides the following two views of snapshots:
  • List view: In this view, snapshots are displayed in a list, including the name, type, size, creation time, and supported operations.
  • Topology view: In this view, snapshots are displayed in a hierarchical tree, including snapshot chain and snapshot node. You can locate the current snapshot, reset canvas, zoom in or out the canvas, and enter the full screen of the view.

Scenarios

Snapshots can be used for the following scenarios:
  • Fast recovery from breakdowns: If the production environment breaks down, you can rollback snapshots to return to the normal state. Snapshot rollback is a temporary use for unexpected breakdowns. To backup data for a long term, we recommend that you use Backup Service.
  • Data exploration: You can create snapshots for production data and use the snapshots to do data mining, query, and development and test.
  • Fault tolerance improvement: Before you perform a business-sensitive operation such as upgrading your system or migrating data, we recommend that you create one or more snapshots. This allows fast recovery to the normal state in case of any errors or exceptions during the operation.