Help required for Service Group planning for Global Clustering!

Most replication agents should work in an RDC or GCO.  The only agent I know that didn't work in an RDC was an early version of the ODG agent as ODG is a host based repliction product that needs to talk to the DR node and it used the global "haclus" commands to communicate with the other cluster, but this was corrected in later agent so it now works in an RDC.  Most replication agents don't need to communicate with the other cluster and the netapp snapmirror agent should be one such agent as netapp snapmirror is array based, not host based replication, so there should be no need for the agent to talk to the remote node.  

Support of replication agents in an RDC is a little "grey" - some agents like SRDF, specifically say they are supported in an RDC, but others like EMC Recoverpoint and netapp snapmirror, do not mention they are supported in an RDC, but neither do they say they are not supported in an RDC or ONLY supported with GCO.  Recently I had a customer who had being using EMC Recoverpoint for over a year in an RDC when Symantec were checking system and they said it wasn't supported, but later they said it was ok.  The netapp snapmirror says:
"You can use the agent in global clusters that run VCS",

not "you must", or "you can only"

and

"If you plan to configure the agent in a global cluster"

- the word "if" to me definatley signafies to me that you do not have to use in a global cluster, which implies you must be able to use it in an RDC as this is the only other choice.

From a technical point of view an RDC is setup as follows:

1. Use Servicegroup system zones to specify which nodes are local and which are remote, so for instance if you haves nodes A and B at prod site and node C at DR site, then configure:
   SystemZones = { nodeA = 0, nodeB = 0, nodeC = 1 }
   
   This means VCS will try to fail WITHIN a system zone, so does not fail across sites unnecessarily
    
2. If you ony want to fail across sites manually, which is the default in GCO and is what I would recommend in RDC, then set ServiceGroup attribute AutoFailOver to 2 - see extract from VCS admin guide for AutoFailOver = 2:
   VCS automatically fails over the service group only if another suitable node exists in the same system zone.
   If a suitable node does not exist in the same system zone, VCS brings the service group offline, and generates an alert for administrator’s intervention
    
3. You will need to localise any resource that have different attribute values when running at DR.  The Netapp snapmirror resource is one such resource which will have something like:
   LocalFilerName@NodeA = netapp1
   LocalFilerName@NodeB = netapp1
   LocalFilerName@NodeC = netapp2
   RemoteFilerName@NodeA = netapp2
   RemoteFilerName@NodeB = netapp2
   RemoteFilerName@NodeC = netapp1
   
   You will also need to localise LocalFilerPword and RemoteFilerPword if the password is not the same on each filer

Mike