VM snapshots

#What a VM snapshot is

A VM snapshot is a copy of a virtual machine's root disk at the moment you take it. Restoring it puts that disk back and reboots the machine; its addresses, security group and attached volumes stay as they are.

A VM snapshot covers the root disk only. A volume attached to the machine has snapshots of its own.

Snapshots are taken by hand. There is no daily schedule, so take one before any change you might want to undo, such as a package upgrade, a migration or a config change you are not sure of.

#Take a snapshot

1. Open the machine and go to its Snapshots tab. You can also use Take snapshot in the machine's ⋯ menu on the list.
2. Press Take snapshot now.
3. Name it after what you are about to do, like pre-nginx-upgrade, and confirm.

A snapshot is ready in about 90 seconds. The tab lists it as soon as the platform records it, marked Creating until the copy finishes, then Ready.

Every snapshot stores the whole disk, not just the part in use, and is billed until it is removed.

#Restore a snapshot

Restoring replaces the root disk and reboots. Everything written to the root disk since the snapshot was taken is lost, and it cannot be undone.

Before you start:

• Take a snapshot of the current disk. It is the only way back if the restore is not what you wanted.
• Make sure nothing is mid-write. A database comes back as if from a power cut; stop it first if you can.
• Tell anyone who depends on the machine. It is unreachable until it has rebooted.

The machine must be running and the snapshot Ready. Then either:

• On the machine's Snapshots tab, press Restore on the snapshot's row, or
• Open the snapshot from VM snapshots and press Restore. This page lays out what changes and what stays, offers Snapshot current disk first, and asks you to type the machine's name.

Confirm with Restore and reboot. The machine shows Restoring, then comes back running from the snapshot.

#Find your snapshots

VM snapshots under Compute lists every machine's snapshots. Open one to see what it was taken from, its size and when it was taken.

#Removing a snapshot

Open the snapshot and press Delete in its Delete card, then type its name to confirm. The copy is removed for good and can't be restored; its storage stops being billed once the platform confirms. Destroying a machine keeps its snapshots, and they keep billing until you delete them.