How snapshots work

A snapshot is a copy of a TIR Virtual Machine’s disk at one moment. Use one to return a VM to an earlier state, start a new VM from an existing disk, or keep a copy before a risky change.

What a snapshot holds

A snapshot holds only the VM’s own disk. The VM’s settings, its datasets, and its shared file systems are left out of it.

The files in a snapshot are consistent when the VM is running and responds to the snapshot request. In every other case, including a stopped VM, the snapshot is crash-consistent: the disk is as it would be after a power cut.

Manual and scheduled snapshots

Manual snapshots are the ones you take yourself, and they stay until you delete them. Scheduled snapshots are taken by a schedule you set on a VM: every six hours, daily, weekly, or on a custom cron timetable. Each schedule keeps the number of snapshots you set, from 1 to 60, with 7 by default. Once a schedule has taken more than that number, it removes its oldest scheduled snapshots first. A schedule removes only the snapshots it took itself. A scheduled snapshot is named scheduled-snapshot- followed by the date and time in India time.

Turning a schedule off stops new snapshots and keeps the old ones. See Schedule VM snapshots.

The statuses

A snapshot is In progress while TIR takes it, then Ready or Failed. You can restore it, start a new VM from it, or use it as the source of an Auto Scaling Group only once it is Ready.

A snapshot outlives its VM

Your snapshots stay when you delete their VM. You can still delete such a snapshot or launch a new VM from it. Restore, Rename, and creating an Auto Scaling Group need the source VM to still exist. In the list, the Source VM of such a snapshot carries a VM deleted badge.

What a restore replaces

Restore replaces the VM’s disk with the snapshot. Changes made since the snapshot was taken are permanently lost, and the VM is offline until the restore completes. The VM stops, gets a disk built from the snapshot, and starts again; its status reads Stopping, Stopped, Starting, then Running. To keep the VM’s current disk, take a new snapshot first, or create a separate VM from the snapshot instead. See Restore a VM from a snapshot and Create a VM from a snapshot.

Sizes and billing

The snapshot list shows two sizes. Disk Size is the size of the disk the snapshot was taken from, such as 30 GB; a new VM from the snapshot needs a disk at least that large. Full Snapshot Size is what the snapshot holds beyond that disk, shown in KB, MB, GB, or TB, and it is a dash until the size has been measured. Snapshots share data with the live disk and with each other, so deleting one may free less space than Full Snapshot Size shows.

Snapshots are billed for the storage they hold, for as long as they exist. For prices, see E2E’s pricing page.

To take your first one, go to Get started with TIR Snapshots.