Question

How should you back up your data on a virtualized system? Data is the most important aspect of your computer. The operating system can be reinstalled and so can applications, but it may be difficult or impossible to recreate your original data. It is essential that you always back up your important information and have a plan for recovering from a system failure. An attacker could crash a computer's operating system or data may be corrupted or wiped out by a hardware problem. Computers can be lost, stolen, or destroyed in a fire or other catastrophe.

But how should you back up your data? What is the best way to back up data on a virtualized system? Should you back up the virtual instance itself? Should you back up the database? Both? What are the advantages of one over the other?

**DO NOT COPY & PASTE

Answer 1

Backups that use OS agents on virtual machines must navigate through the virtualization layer to get to the guest operating system layer. A more efficient way of doing backups in virtualization is to perform the backup at the virtualization layer and never enter the guest operating system. VMware recognized this and released its VMware Consolidated Backup (VCB). VMware Consolidated Backup acted as a proxy server to offload the backups from within the virtual machine by mounting the virtual disk on the VMware Consolidated Backup server and then doing an image-level backup of it without involving the host or the virtual machine. This shifted the backup overhead from the VM and the host to the proxy server instead. While this was a step in the right direction, it required a middleman between the backup device and the target disk.

The typical approach of backup the database involves an agent running on the [backup] client that reads the source data and copies it across an IP network to a backup server. The backup server in turn then transfers that backup data to the backup target. The location of each file within that backup is recorded into a database for restoration purposes.

The same approach can be used for backing up a virtual machine. In fact, it offers, from a conceptual point of view, the simplest approach. Each virtual machine can have a backup agent installed, which would read its own data and transfer that data over the network to the backup server. The backup software would have no knowledge whether the server is virtual rather than physical.