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Snapshot, Backup or Replication

Paragon Software Group | May 6, 2016
We find out the differences between basic data management techniques, such as snapshot, backup and replication.

Snapshots of virtual machines are primarily made for testing purposes. For instance, they are excellent for undoing recently changed configurations or rectifying problems from improperly run software.

However, using snapshots instead of backups will impair the performance of the virtual machine. You will also run the risk of losing data. Reduction in performance might be tolerable, but the loss of data or vital applications could ruin a company's business operations altogether. Furthermore: Who wants to sacrifice storage capacity and performance if it's not absolutely necessary?

Backups are not snapshots!

In most virtual systems, the snapshots and original virtual disk are stored at the same location. If the original data medium is lost, then the snapshots - and thus the data - will be irretrievably destroyed. Snapshots have a slew of useful properties and are perfect for temporarily backing up a system while the virtual machine is being updated. If a problem appears, a snapshot can be used to restore the system to its original state. Deleting the snapshot is all it takes to make faulty modifications history. But if everything works properly, the changes are simply used on the original virtual disk. Snapshots are practical and extremely helpful in many situations, but they are no substitute for a proper backup.

In most virtual systems, the snapshots and the original virtual disk reside in the same location. If the original virtual disk is lost, then the snapshots - and thus the data - will be irretrievably destroyed.

Snapshots have a slew of useful properties and are perfect for temporarily backing up a system while the virtual machine is being updated. If a problem appears, a snapshot can be used to restore the system to its original state. Deleting the snapshot is all it takes to make the faulty modifications history. But if everything works properly, the changes are simply used on the original virtual hard drive.

Snapshots are practical and extremely helpful in many situations, but they are no substitute for a proper backup.

Backup creation is a multi-level process: An exact and complete copy of the virtual machine is created, then moved to a new storage location, and normally compressed in the process as well. Depending on the backup solution used and its configuration,

the copy is either compressed before or after it is transferred to the target storage. Both variants have benefits and drawbacks, so they should be chosen based on specific requirements. The compression on the original system reduces the system's processing power, but enables significantly more efficient transmission over a network.

However, by far the most important aspect of creating a backup is the creation of a consistent copy of the virtual machine. And even though a snapshot should not be considered an actual backup solution, it is an integral part in the backup process. Most existing backup solutions for ESX / VSphere environments are based on VMware-native snapshot technologies.

 

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