Obtain used block information of VMDK in ESX 3.5

gangan2000 · ‎05-21-2010

How to use vStorage API to obtain used block information (for baseline full backup only) in ESX 3.5 VM disk? Like using QueryChangedDiskAreas with ChangeID "" in VSphere 4.0. I tried using QueryChangedDiskAreas with changeID "" for ESX 3.5 VM's disk and it throws MethodNotFoundFault. I understand we can't use CBT in ESX 3.5. But not sure which vStorage API or method to get the "used block ranges" for ESX 3.5 VM disk.

Thanks in advance.

lamw · ‎05-21-2010

VMware has excellent documentation with using the vStorage API for Data Protection under their VDDK API section - http://www.vmware.com/support/developer/vddk/

Specifically, take a look at vStorage APIs for Data Protection documentation that explains how to design and create a backup solution

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gangan2000 · ‎05-21-2010

Thanks William.

I am following both documents closely. I don't have any difficulties to obtain used block information for vSphere 4 VM disks. But it is unclear how to get used block information for "ESX 3.5" VM disks using vStorage API (for baseline full backups only).

lamw · ‎05-21-2010

I don't believe this is available using the existing APIs, at least the ones public exposed. I know some 3rd party backup vendors has done something similar in calculating the change blocks, before CBT came out with vSphere, though I'm not sure if that is done using VMware's API. I believe they probably have to read the VMDK somehow to figure this out, whether that's with VDDK or some other tool.