What is a Snapshot?
A snapshot is a point-in-time copy of a server's entire state, including the operating system, installed software, configurations, and data. Snapshots allow you to capture the current state of a virtual machine or disk and restore it instantly if something goes wrong.
How Does Snapshot Work?
Snapshots work by recording the state of a disk at a specific moment. Rather than copying all data, most snapshot implementations use a copy-on-write mechanism that only tracks changes made after the snapshot was taken, making them fast to create and storage-efficient. This allows you to take a snapshot before performing risky operations like software upgrades or configuration changes.
While snapshots are invaluable for quick recovery, they are not a replacement for proper backups. Snapshots typically reside on the same storage system as the original data, so a hardware failure could destroy both. They also accumulate storage overhead as changes grow. Best practice is to use snapshots for short-term rollback protection and maintain separate offsite backups for long-term disaster recovery.