We are planning our 5.5 to 6.0 upgrades. Two sites have SRM involved. We would like to be able to deploy in such a way as to make long distance and cross-vCenter vMotion possible in the future. However it seems these may be incompatible with SRM.
Cross-vCenter vMotion requires enhanced link mode. Enhanced link mode requires the vCenters to use the same PSC. A dependency between the protected site and the recovery site as would be created by putting the two SRM vCenters in linked mode is a non-starter. You need to be able to log in to your recovery site vCenter if the protected site is blown away by a tornado.
Maybe the answer is; cross-vCenter vMotion is incompatible with SRM unless you create the deployment model with redundant load balanced PSC servers. Locating one PSC geographically separated from the protected site. Even in that scenario, it is unclear to me if you would have to re-point the recovery site vCenter in a disaster. Again, I think enhanced vMotion literally requires the 2 vCenters to be pointed to the *same* PSC, not just PSCs in the same SSO domain.
I have a case open with VMware and I will share the results if it's helpful. Both protected site and recovery site use our corporate Active Directory as the identity source but I don't think that will help us if we are in linked mode and lose a PSC.