Snapshots are NOT backups

A virtual machine snapshot is not a copy so it cannot be treated as a direct backup. A snapshot file is simply a log of changes to the original virtual disk. The virtual machine is running on the most current snapshot, not the original vmdk disk files. To reiterate: snapshots are not copies of the VM's original vmdk disk files. Taking a snapshot does not create a complete copy of the original vmdk disk file, rather it only copies the delta disks.

Side effects of running with snapshots

• Decreased performance if there are too many delta files in a chain (caused by having too many snapshots).
• Decreased performance if delta files become too large.
• Cannot increase Virtual Disk size while snapshots are active.
• Delta files can grow to the same size as the original base disk file: a virtual machine's provisioned storage size can grow to ( its original size ) multiplied by ( the number of snapshots ).

Recommended Reading

• Understanding virtual machine snapshots in VMware ESXi and ESX (VMware KB Article 1015180)
• Best practices for virtual machine snapshots in the VMware environment (VMware KB Article 1025279)

Requesting a Snapshot

To request a snapshot for your VM, please use one of the following methods:

• Fill out the following Snapshot Request form.
• Use the EIS Virtual Cloud RESTful API - How to schedule a VM snapshot

Reverting to a Snapshot

To revert a VM to (or from) a specific snapshot, please use one of the following options:

• Send an email to vss(at)eis.utoronto.ca.
• Use the EIS Virtual Cloud RESTful API