I am currently having VDR backing up to a 700GB VMDK on a VMFS datastore that has been attached as a local hard drive. I am starting to get a lot of errors, -102's and -2249's as of late and I am wondering if I have to keep the VMDK's at 500GB or smaller like you do with CIFS shares or else you just run into endless integirity checks.
I have ran VDR in past with 600GB backup volumes with no issues. I am assuming that you are running vDR 2.0, it has a 1 TB backup volume limitation. The following web blogs talks in details about VDR features and limitations in detail. https://techontip.wordpress.com/2011/07/25/understanding-vmware-data-recovery/