VMWare Consolidated Backup

VMWare Consolidated Backup

Written by Damian Murdoch   

Wednesday, 21 June 2006

VMWare Consolidated Backup

A few people have asked me exactly what VMWare Consolidated Backup is and what it can do.
This article will try and explain exactly that.

VCB has been designed to improve the backup infrastructure of a virtual environment in a number of ways.
These include :

•  Leveraging technology found in VMWare products to improve the standard filesystem backup. These technologies include those found in the VMFS and the ability to snapshot a server and write the changes to a redo log while you perform a backup of the files found in that snapshot.
• Removing heavy backup cycles from the ESX server. Normally an organisation's backups run at similar if not the same time, this incurs a huge CPU time cost on the virtual host. With VCB, this can change as backups are moved to one or more backup proxy's which then handle the load. 
•  VCB also reduces the cost of this backup technology as it will work on a SAN without vendor supplied and mostly expensive software to perform the same type of tasks. This reduces the complexity of the backup environment and still remains simple to implement and maintain!
• VCB eliminates the need for backup agents on each virtual machine as the backup proxy performs the data backup to removable storage.

VMware Consolidated Backup is a seperate product and is licensed as such, it also is NOT backup software. VCB enables you to perform backups of data but does not actually perform the backup. To perform the backup you still need software such as Netbackup, Legato and the like.

So what does it actually do ?

The simple explanation of VCB is that it will quiesce a virtual machine, and open that machines vmdk files up to access by the backup proxy. This allows it to either copy the data as a complete filesystem out of the machine or to back up the vmdk file as a whole. While the machine is in this state all of the changes are written to a redo log which is applied when VCB has finished.

VCB looks like a great product and it will only get better. Keep in mind one thing though, it is not a point and click backup and restore interface and it is not backup software. It is backup ENABLING software. The major backup software vendors are in the process of writing integration kits to work with VCB and this is where it will come into it's own.

VCB is only for windows guests and does not have linux support *YET*

Currently VCB is only for backup and does not have a restore function. To restore you have a couple of options which are :

•  restore whole vmdk files to service console and move the files to the target VMFS file system. Then make sure your VM's are configured to use them
• Set up a restore box. Restore to the server and move the data after this point. You can also put an agent inside each VM and restore the files directly to the target if you wish. The restore is a backup software thing, not a VCB thing.

Still an early version of the product, but looks promising!