If your VM's were created in VSphere 5, CBT will be on by default.

My understanding is that either way (starting with CBT on or off), you should 
only get USED space on the first backup.


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Michael Roesch
Sent: Monday, July 08, 2013 4:29 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Should CBT be enabled before using TSM for VE to save space?

Hi there,

I've read here http://www-01.ibm.com/support/docview.wss?uid=swg21608413 that 
TSM for VE is using "content-aware" backup, if CBT is enabled. It also says 
that TSM for VE will enable CBT after the first backup.

So I'm wondering if enabling CBT before performing the first backup would make 
TSM for VE backup only the used blocks (i.e. used space) and hence would save 
space on the storage pool?

Or would TSM for VE still backup the full VMDK, including possible lots of 
unused space inside it on the first backup?

Regards,
Michael