Virtualized computing environments may employ a variety of backup strategies. One of the most useful is the image level backup. This technique is supported by most backup tools designed for use with virtual machines. Indeed, it is considered the best way to back up the data on VMs.
An image level backup works primarily inside the virtualized layer of the information environment. This allows it to largely ignore the details of the operating system, resulting in a backup operation that uses fewer resources overall and is generally more efficient. However, deciding to back up entire VM images should not be done without first implementing some sensible limits and controls.
For example, some blocks may be entirely empty of data while others may contain only data that has been deleted by users. Such data may persist until the space occupied is needed again, at which point the deleted data will be overwritten and will be permanently lost. In the meantime, however, the data exists but does not need to be backed up. A sensible control solution is to make sure that such blocks are not included in the image level backup.
Other considerations for image level backups include the use of deduplication technology to reduce the amount of redundant data. Compression algorithms can also help to lower the total space that backups need.
Backing up VMs is an important business activity, best done under a managed program model of IT solutions. With this approach, qualified staff will be on hand during backups to supervise the procedure so that space is not wasted and data are not lost.