More than Veeam CDP supporting RDM, I'd wonder if VMware VAIO libraries do, and I highly doubt it. Exactly like snapshots and other techs, VAIO premise is that the IO goes through the hypervisor stack in order to be filtered and processed, with RDM (exactly like in-gues iscsi as another example) data totally bypass this stack and go straight to the volume.
I only found for now this blog (https://dpzoneblog.wordpress.com/2016/0 ... t-title-2/
) talking about recoverpoint and seems indeed that VAIO does not support RDM.
PS: Zerto does not use VAIO libraries, so it may be that they support RDM. It's funny that such applications are so interested in certifying data protection solutions (and that's good) and then the accept a solution that not even the underlying hypervisor supports (https://kb.vmware.com/kb/2069900