Snapshots

Snapshots

Snapshots are the reciprocal of volumes. When a snapshot of a volume is created, a differential backup of the devices is created and stored in S3. From this snapshot, a clone of the original volume can be created. enStratus leverages this property of snapshots when automating application deployments. At the time of this writing, snapshot creation is only supported by the Amazon EC2 cloud.

Creating Snapshot

To create a snapshot of a volume, select the volume and click on the green action button, choosing make_snapshot. A dialog box will appear requiring a name for the snapshot and an optional group and billing code.

A job will start in the background and the snapshot will added to the list of snapshots in Infrastructure > Snapshots.
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Creating Volumes from Snapshots

Creating volumes from snapshots is a way to create an exact duplicate of the volume from which the snapshot came. If the filesystem on the volume supports increasing the size of the volume, the volume created from the snapshot may be increased in size.

The volume created from the snapshot must be at least the size of the original volume.

To create a volume from a snapshot, navigate to Infrastructure > Snaphots and select a snapshot. Click on the appropriate actions button and choose create_volume. The resulting dialog box allows for the customization of several options, including standard enStratus options of name, group, and billing code.

The size field will automatically be populated with the size of the original volume, but can be increased. For Amazon, volumes are specific to an availability zone, so a zone is required for volume creation.

The created volume will soon appear in the Infrastructure > Volumes page for selection and attachment to servers.

Sharing Snapshots

Sometimes it is advantageous to share snapshots to another account for ease of data transfer. Sharing snapshots in enStratus is accomplished by selecting the snapshot to share and clicking on the action button choosing sharing.

A dialog box with two primary options is presented. The first share type is Private. Private sharing enables an enStratus user who is a part of several accounts to share snapshots between those accounts. The accounts of which the user is a part will populate a dropdown window. Once the snapshot is shared, the snapshot will appear in the other account.

The second share type is Public. Public sharing enables an enStratus user to add a snapshot to the publicly available pool of snapshots. This is an option that carries the risk of making publicly available private data, so this action should be restricted using enStratus groups and roles.

Snapshot Strategies

Because snapshots are differential backups, the time snapshots take to create varies based on the amount of changed information since the last snapshot was taken. Frequent snapshots will generally be created more quickly than infrequent ones.

In an automated environment with enStratus, it is possible to have enStratus automate both the creation of snapshots and recovery volumes according to a customizable schedule.
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