Snapshots

A snapshot is a way of making a copy of a disk state so it can be preserved. You can create a snapshot of the root disk of a virtual machine or of volume storage.

Contents

• Instance Snapshot
• Snapshot of Volume Storage

Please visit Nectar Tutorial Website for a step by step guide to make snapshot.

Instance Snapshots

A snapshot is a way to create a copy of the disk state of your virtual machine (VM).
There are are a number of reasons for taking a snapshot of a VM:

1. To back-up the VM set-up - you can restore an instance from the snapshot.
2. To create a template image which can be used to launch instances which are already set-up.
3. To relaunch an instance as a new VM with a different flavor  (increased Tech Specs) or in a different Availability Zone.
4. To share the set-up of a VM with other users.  (Ask the helpdesk for help in making your snapshot available to another different project.)

NOTE: The snapshot only creates an image of the primary 'root' disk, not the secondary 'ephemeral' storage or mounted volumes.

The primary 'root' disk is small (5-30GB) and is not suitable for storing significant data. Creating an image of your VM is preserving the computer set-up such as software installation, configurations and profiles. Follow this link for  "Backing up Data".

To creating a Snapshot of an Instance (an Image), follow our tutorial here. 

To launching an Instance from a saved Image, follow our tutorial here. 

NOTE: The new VM launched from a saved image will have a new, empty ephemeral disk. This will need to be made writable with the command:
sudo chown ubuntu /mnt

If required, existing volume storage will need to be attached, mounted and made writable also.
On the Nectar Cloud Dashboard, navigate to Project -> Volumes -> Volumes -> Manage Attachments
Then access the VM command line and enter:

sudo mkdir /volume_name
sudo mount /dev/vdc /volume_name -t auto
sudo chown ubuntu /volume_name

Contributed Images

Snapshot images can be made public or they can be submitted as "Contributed Images". Contributed images are public images that fulfil standard criteria for quality assurance. Information on submitting a contributed image is found here.

Snapshots of Volume Storage

Snapshots can also be made to copy the disk state of your Volume block storage. This is useful for preserving the state of your Volume in an image, in order to create a new Volume from it at a later time. The volume snapshots use up your volume data allocation, for the full size of the volume. 

NOTE on limitations of volume snapshots:

1. Volume snapshots are not designed as a method of backing up data. They don't create a separate physical copy. (If the volume storage servers are down for an extended period, you won't be able to access the snapshots either.) See data backup suggestions here.
2. Volume snapshots cannot be used for migrating volumes between Availability Zones. The original volume, the snapshot and the new volume must all be in the same zone.

A tutorial for creating snapshots of volume storage can be found here.