Virtual Machine Backup

VMware suports hot backups and supports two technologies for backups

There are new features in version 4.1

It is possible to backup a running VM, this is achieved either by VMware or a 3rd party vendor leveraging VMware's snapshot feature. As discussed in my virtual machine section, when a snapshot is applied to a VM, the files that make up the VM becomes unlocked in the file system, when the files are unlocked it is possible to back them up. The only thing to worry about is the validation that the snapshots were successful prior to creating the backup and that they are deleted after the backup has finished or crashed, remember these snapshot files can grow to a very large size. VMware introduced a file system sync driver installed into the VM during the installation of VMware Tools. The job of this sync driver is to flush the file system cache, forcing a write-to-disk prior to the backup process, thus you b=get the most complete backup you can have with a live running VM. The newer version of the sync driver now has hooks into Microsoft's Volume Shadow Copy Service.

If you have a small environment or a laptop with VM running you could simply stop all the VM's and clone as templates in the compressed format to a different storage location. In a normal world you would backup the VM from the SAN itself, without the need for backup agents installed into the guest O/S, however many companies still install a backup agent (for example Netbackup) in the guest O/S.

VMware has developed it's own backup APIs which the conventional 3rd party vendors can hook into. VMware Consolidated Backup (VCB) isn't actually a backup solution, but rather a collection of command-line tools, scripts and drivers that allow an existing backup vendor to use its backup solution for Windows to access VMFS volumes and files within the VM.New to vSphere is the VMware Data Recovery (vDR) appliance, which is a downloadable virtual applicance thata assists in the backup process.


Vdr comes with a point and click interface, it works with ESX classic and ESXi, it inclkudes features such as compression of deduplicated data, there is no network hit when used with shared storage. After the first backup all subsequent backups are merely the delat changes within the virtual disk using special change-block-tracking functionality. However vDR only works in vSphere 4, you can backup 100 VM's and only once in 24 hour period.

I suspect that these limitations will be removed as the technology progresses.

VCB VCB works with both vSphere 4 and VI3, you require no additonal purchase or education investment, you can use the same tools to backup physical and virtual machines. It does not have deduplication and is not capable of backing up a full VM and then recording the delta changes after the first backup. The backup load is removed from the network and the ESXi server by means of a dedicated physical Windows server with a connection to your SAN, iSCSI or NAS system. This solution is popular with large environments especially if you have older versions of VMware.

Using vDR

At this time I am unable to show you vDR until I get a copy of the software

Using VCB

At this time I am unable to show you VCB until I get a copy of the software