To simultaneously operate both mirrors in SRDF/A mode, the concurrent R1 device must reside on a Symmetrix array running Enginuity 5875 or higher. The R2 devices can reside on any Symmetrix array supporting connections to a Symmetrix array running Enginuity 5875 or higher.  From SRDF product CLI guide.  regards, Saurabh Rohilla
Got an error "Only one remote mirror of a Concurrent RDF device can be in Asynchronous mode at any time" while setting mode async for a RDFG.Any idea why I got this error?
Only one remote mirror of a Concurrent RDF device can be in Asynchronous mode 
at any time