Full Backup vs. Snapshot: What’s the Difference?

If you are running a KVM VPS at InterServer, your system is built on the ZFS file system. One of the biggest perks of ZFS is that it allows for snapshots.

It is easy to mix up “snapshots” and “backups,” but they work differently and protect you from different things. Here is how to tell them apart so you know which one to rely on when things go wrong.

Snapshots: The “Undo” Button

Snapshots are automatic. In most cases, they roll in 24, 48, and 72-hour increments.

A snapshot is a point-in-time rollback point for your VPS. It is not a full copy of your data stored somewhere else. Instead, it freezes the file system at a specific moment and tracks changes from there.

Here is an example of how it works:
Imagine a snapshot is taken automatically at 6:00 AM on a Tuesday.

• From that moment on, the snapshot holds the “base” image, and the system tracks any changes you make.
• If you break your configuration on Wednesday, you can roll back to the Tuesday snapshot.
• The system reverts all changes made since 6:00 AM Tuesday. The server is exactly as it was at that time.

Because snapshots only have to manage the changes rather than copying the whole drive, they are generally much smaller and allow for a very quick restore.

The Catch:
Snapshots live on the same physical hardware as your VPS. They do not survive hardware failures. If the node your VPS sits on has a drive failure, the snapshots are lost along with the VPS.

Full Backups: The Safety Net

You can create full backups manually in the backup section of your control panel.

Unlike a snapshot, a full backup creates a complete image of your file system and sends it to a remote system. This separates your backup from your live server.

• Pros: This is a true backup. If the hardware node completely fails, your data is safe on the remote system and can be restored.
• Cons: Because these are large files stored remotely, restoring them takes longer than rolling back a snapshot. You have to transfer the data back over the network.

Summary of Differences

Feature	Snapshot	Full Backup
Storage Location	Local (Same disk as VPS)	Remote (Different server)
Restore Speed	Fast	Slower
Hardware Failure	Will not survive	Will survive
Best Used For	Fixing bad updates or mistakes	Disaster recovery

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A Note on Single File Restores

Both snapshots and full backups are designed to roll back the entire system. They are great if the whole server breaks, but they aren’t helpful if you just deleted one important file.

Restoring a single file from a full system image is complicated and time-consuming. It is best to have a second backup method (like cPanel backups or a cloud tool) specifically for restoring individual files.