Before you begin:

• All client and server systems must be at a currently supported release level.
• DFSMSrmm on z/OS V1R12 and later releases is an IPv6 enabled application that supports both IPv4 and IPv6 sockets. You can continue to use IPv4 on all systems or you can run a mixed environment with one or more V1R12 systems using IPv6 and other systems using IPv4. Once all systems are V1R12, you have the option of moving all systems to IPv6. In a mixed environment, dual-mode IP stacks are required. Refer to z/OS Communications Server: IPv6 Network and Application Design Guidefor more information.DFSMSrmm client/server processing is dependent on Internet Protocol V4.
• You can share the control data set with other systems that run any supported level of DFSMSrmm with any supported level of DFSMSrmm that has appropriate toleration maintenance installed.

You can convert existing DFSMSrmm systems to be either client or server systems, or add new DFSMSrmm systems to the RMMplex. In addition you can merge existing DFSMSrmm systems into the RMMplex by merging the control data sets as described in the IBM Redbook DFSMSrmm Primer, SG24-5983.

• To implement a client system, follow these steps.
  1. Ensure TCP/IP definition files are updated to identify the server host name, IP address, and port number.
  2. Ensure that the RACF user ID associated with the DFRMM started task is configured correctly. Refer to "Requirement for an OMVS segment" in z/OS Communications Server: IP Configuration Guide.
  3. If you have a firewall installed, update your firewall to ensure that communication between DFSMSrmm clients and servers is allowed only for the defined IP addresses and ports. The DFSMSrmm subsystem does no authentication, encryption, or verification of connect requests received on the server other than to verify that it is a valid DFSMSrmm request and that the control data set IDs match. You should also consider using RACF to protect the use of the IP addresses defined for DFSMSrmm and to limit the use of the IP address to the DFSMSrmm started task.
  4. Update the parmlib options with the CLIENT operand and select appropriate values for the sub operands. The parmlib operand, CDSID, has to be the same as on the server. If CATSYSID is not already set, add the operand now to define the list of system IDs that share catalogs with the client system or specify that catalogs are shared. Define the list of system IDs that share catalogs with the client system (CATSYSID(list)) or specify that catalogs are shared (CATSYSID(*)).
  5. Refresh DFSMSrmm with the new EDGRMMxx parmlib member.
  6. Run EDGHSKP CATSYNCH to synchronize catalogs if needed.
  7. Run EDGHSKP with EXPROC regularly to return volumes to scratch status.
• To implement a server system, follow these steps.
  1. Update the parmlib options with the SERVER operand and select appropriate values for the sub operands.
  2. If CATSYSID is not already set, add the operand to define the list of system IDs that share catalogs with the server system or specify that catalogs are shared.
  3. Ensure that TCP/IP definition files are updated to identify the server host name, IP address, and port number.
  4. Ensure your firewall is updated with the client and server IP addresses and port numbers.
  5. Refresh DFSMSrmm with the new EDGRMMxx parmlib member.
  6. Run EDGHSKP CATSYNCH to synchronize catalogs if needed.
• You must perform these steps to implement a standard system that is part of an RMMplex that contains client and server systems.
  1. If CATSYSID is not already set, add the operand to define the list of system IDs that share catalogs with the server system.
  2. Refresh DFSMSrmm with the new EDGRMMxx parmlib member.
  3. Run EDGHSKP CATSYNCH to synchronize catalogs if needed.