Creating and Managing Server Snapshots

Updated by Chris Little on Oct 24, 2016

Overview

Snapshots are a feature of our platform that allow a machine to be quickly reverted back to a set point in time. This can be very useful for things such as short term testing of updates or configuration changes. However, due to the way that snapshots operate they should not be kept active for extended periods of time . A snapshot is not a backup of a machine and should not be used as such! Snapshots do not contain a duplicate copy of the machines data rather they operate more like a change log that starts from the point in time the snapshot is initiated. Due to the nature of their operation snapshots are in a constant state of growth from the time they are created and the larger a snapshot becomes the longer delete or revert operations of the snapshot will take. If left active for an extended period of time snapshots also have the potential to completely fill the storage the machine is housed on causing many additional problems. In order to avoid these performance issues snapshots should not be kept active longer than 10 days. Any snapshot active longer than 10 days WILL be removed without notice as part of our maintenance process.

Snapshot Implications

  • Using snapshots with a very high rate of change can cause significant performance degradation when the snapshot is removed. Your server may lose connectivity or become unavailable for several minutes or longer during the removal process.
  • Snapshots are not supported on Standard Virtual Servers with greater than 1 TB of Storage Allocated. Hyperscale Servers cannot leverage the Snapshot feature.
  • Configuration changes to Virtual Servers, such as CPU/RAM/Disk, cannot be performed while a snapshot is present.
  • Cloning of virtual servers with a snapshot is a supported operation. Please review How To: Clone a Virtual Machine for more information.

Create a snapshot of an existing server

  1. Select the Snapshot button on the server details page.

    Select snapshot button

  2. Choose the snapshot lifespan. Snapshots created by users must be deleted within 10 days.

    choose snapshot lifespan

  3. After the job is completed, the user can see their snapshot on the server details page. A server can only have a single snapshot at a time. The snapshot entry shows the date the snapshot was taken.

    snapshot server details

Create a snapshot of a group of servers

  1. Select the Snapshot button on the group of servers you wish to take a snapshot. Choose the Virtual Servers and how long you wish to retain the snapshots.

    perform group snapshot

Restore a server snapshot

Users can use snapshots to restore a VM to its previous state by simply clicking on the snapshot name in the server details. After restoring a server to a snapshot, the snapshot itself is reset and retained.

restore VM snapshot button

restore snapshot dialog box

Delete a server snapshot

Customers can delete a snapshot by selecting the red X next to the snapshot name in the servers detail page.

select delete snapshot icon

confirm delete snapshot dialog box

Summary

The basic points to remember about snapshots:

  • Not a viable form of backup (in fact not a form of backup at all)
  • Useful for short term rollback of changes only
  • Performance issues result from old snapshots
  • Should not be kept longer than 10 days
  • The platform uses the following VMware Options flags in the Snapshot
    • Memory: true; a dump of the internal state of the virtual machine is included in the snapshot.
    • Quiesce: true; VMware Tools is used to quiesce the file system in the virtual machine. Quiescing a file system is a process of bringing the on-disk data of a physical or virtual computer into a state suitable for backups. This process might include such operations as flushing dirty buffers from the operating system's in-memory cache to disk, or other higher-level application-specific tasks.
    • A more technical overview of VMware snapshots can be found on VMware.com

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