I am in the process of evaluting VCB as part of a backup strategy in my company which has both Windows and Linux Guests. I understand that VCB doesnt currently doesn't support file level backups of Linux Guests. I have a few questions re VCB which someone can hopefully answer:
1. If VC is not used, do you need a VCB proxy for each ESX server ?
2. When performing image level backups of VM guest is the snapshot copied to a local mount or is the snapshot just mounted on the proxy server ?
Answer to number 1 is no. One proxy can handle multiple ESX servers.
Number 2 if you do an image level backup the entire virtual machine will be exported and it's contents stored on the VCB proxy.
The snapshot is stored on the VMFS where the virtual disk resides.
Yes the partition/volume used for th VCB mount point can be a SAN volume, the benifit of using a SAN volume is you can easily extend it as needed where as if you use local storage e.g. scsi disks its not as easy as you might not have drive bays free, one disadvantage of using SAN would be cost. It really depends on how many VM's you have and how much data is exported out as part of the Image export.
Hope this helps