VM Backups vs Snapshots
Number of views :
14
Article Number :
KB0012584
Published on :
2023-12-11
Last modified :
2023-12-11 15:30:40
Knowledge Base :
IT Public Self Help
Backup
A backup is a consistent copy of data on a virtual machine (VM) in a virtual environment to prevent data loss. VM backups are created using a conventional third-party backup software.
For more information on backups in the UT-VMG environment, see KB0011600 - Using Backup Self Service.
Snapshot
A snapshot is a copy of the virtual machine’s (VMs) virtual machine disk (VMDK) file, at a specific point in time. Snapshots provide a change log for the VMDK and are used to restore a VM to a particular point in time when failure or errors occur. Although a snapshot does carry some traits of a backup, it is NOT a full backup.
For more information on how to take a snapshot in the UT-VMG environment, see KB0011601 - VM Snapshots.
Key differences between Backups and Snapshots
Backups | Snapshots |
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Best Practices
- Snapshots are NOT backups. A snapshot file is only a change log of the original virtual disk. Therefore, do not rely on it as a direct backup process. The VM is running on the most current snapshot, not the original VMDK files.
- Snapshots are not complete copies of the original VMDK files. Taking a snapshot does not create a complete copy of the original VMDK file; rather, it only copies the delta disks.
- An excessive number of delta files in a chain (caused by an excessive number of snapshots) or large delta files may cause decreased VM and host performance.
- Do not keep a single snapshot for more than 72 hours. Snapshots should not be maintained over long periods of time for application or VM version control purposes.
- Do not rely on snapshots for I/O intensive VMs with rapid data changes, because significant data inconsistencies will occur when the VM is restored.
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