john D. Schneider said:

>The beauty of VCB is that it doesn't require a client install on each
>machine; there is less administration per VM, which means less time.

Hmmm. Not sure I'd use "beauty" and "VCB" in the same sentence. ;)  I
usually say that VCB stands for Very Complicated Backup. ;)

I'm not defending the Avamar method.  I'm just saying the VCB method is not
all that great either -- regardless of which backup product is using it.

With most backup software, you generally have two options with VCB. One
option mounts the virtual disk as a drive letter on the proxy server
allowing you to do progressive incrementals against it.  (I'll call this the
virtual drive method.)  The other method copies the VMDK in its entirety to
the proxy machine's staging disk; this copy is then copied again when it is
backed up via TSM or any other backup software.  I'll call this the image
method.

The virtual drive method is alright, but gives you no way to recover a VM.
The image method allows you to recover the VM, but it requires two full
backups every night.  While you are right about moving the load off the ESX
server, don't forget the load you're placing on your storage infrastructure
doing two full backups every night if you choose the image methohd.  And
don't forget that doing a restore requires two steps as well: restoring to
the proxy server then copying from the proxy server to the ESX server.

My summary statement is that I think that all VMware backup options kind of
stink right now (short of moving your VMware filesystems to a N-series filer
and doing SnapManager for VI).  I therefore think that people interested in
(but not yet using) VCB should wait until TSM supports vSphere, which gets
rid of the stupid two-step backup and two-step restore.

Just my $0.02.