Using VMware Snapshots as Backups – Risks, Best Practices & Alternatives

A bloody lesson! Using VMware snapshots as backup, the business collapsed for 12 hours...

At 3 AM, a piercing alarm suddenly blared in the server room. Operations engineer Xiao Chen sprang up from in front of the monitor screen — the database server of the core business system was completely offline, and the cashier systems of hundreds of stores instantly crashed. No one expected that the source of this 12-hour business disaster was a VMware snapshot, which was treated as an "all-purpose backup."

The story goes back a week. To test new features, the technical team created 3 snapshots on the database server, intending to delete them immediately after testing. But in the rush to meet project deadlines, everyone completely forgot about it. As the snapshot chain grew longer and longer, the performance of the virtual disk quietly began to decline, until one morning, the disk space was completely occupied by snapshot files, and the system directly crashed with a blue screen.

What's worse, the team had always treated snapshots as formal backups. When they found the main system down, they were dumbfounded when they tried to restore the snapshot. The longest snapshot had existed for 7 days, and the accumulated business data from that period had not been synchronized at all. Restoring it meant losing 30% of the transaction records. Even more frustrating, during the snapshot restoration process, file fragmentation errors occurred on the virtual disk, and it took 5 hours just to fix them.

Are VMware Snapshots Backups?

A VMware snapshot captures the state of a virtual machine at a given point in time. While snapshots are useful for testing, patching, and short-term recovery, they are not designed as a long-term backup solution.

Many admins mistakenly rely on snapshots as backups, which can lead to storage issues, data corruption, and performance degradation.

In fact, this is not an isolated case. VMware snapshots are essentially "state freezing tools. "They are like taking an instant photo of a virtual machine, but they cannot replace professional backup:

• Performance Killer

More than 2 snapshot chains can cause IO performance to plummet by 50%. If they exist for more than 3 days, they may trigger a disk fragmentation storm. Even deleting snapshots may lead to the risk of virtual machine consolidation snapshots becoming unusable.

• Data Trap

Snapshot files are tightly bound to the source disk. Once the source disk is damaged, the snapshot will also be rendered useless.

• Capacity Bomb

Dynamically growing snapshot files can consume an entire storage pool within hours, especially in high-frequency read/write scenarios like databases.

The correct approach should be: Snapshots are only for short-term testing (recommended not to exceed 24 hours), combined with scheduled backup tools for complete data protection. After each snapshot creation, set up automatic deletion reminders and check snapshot cleanup weekly.

The direct loss caused by that downtime ultimately exceeded one million, and the team immediately formulated a "Snapshot Lifecycle Management Specification."

Remember: Snapshots are emergency bandages, not long-term safes. Relying on snapshots for backup will sooner or later cost you for that.

Risks of Using VMware Snapshots as Backups

• Storage Bloat: Snapshots grow over time and consume large amounts of disk space.

• Performance Issues: Multiple snapshots can slow down VM performance.

• Data Loss Risk: If the base disk becomes corrupted, restoring from snapshots may fail.

• Unsupported for Long-Term Retention: VMware explicitly advises against using snapshots as backups.

Best Practices for Using VMware Snapshots

• Use snapshots only for short-term testing and before risky changes.

• Delete snapshots after verification to avoid storage problems.

• Limit to 1–2 snapshots per VM whenever possible.

• Monitor datastore usage to avoid unexpected out-of-space errors.

Interactive at the end of the blog: What virtualization backup pitfalls have you encountered? Share your solutions in the comments below.