RMM GRS recommendations

Ensure that the volume where the DFSMSrmm control data set resides does not contain any other data on it. The handling of the SYSZRMM MASTER.RESERVE resource depends on how the SYSIGGV2 and SYSZVVDS resources are being treated. Ideally these resources are all being sharing inside the GRSPLEX and can be converted from using real hardware reserves by putting them all in the GRS CONVERSION RNL. SYSZRMM MASTER.RESERVE is by default managed as a hardware reserve and in some circumstances can get into a deadlock with Catalog if all of these resources are not in the same GRS RNL list. If you are converting the SYSIGGV2 resource for the ICF Catalog that contains the RMM CDS, then you should also consider converting SYSZRMM MASTER.RESERVE resource and the SYSZVVDS resource for the specific volume that the RMM CDS resides on.

If the volume contains other critical data and real reserves could impact other systems or cause DASD contention problems, we recommend converting the RESERVE to a SYSTEMS enqueue. If you make no changes to your GRSRNLxx parmlib member, then DFSMSrmm still functions correctly; but any performance gain from using the real hardware reserve feature is negated by the additional unnecessary overhead of sending the global SYSTEMS enqueue around the global resource serialization ring.

The previous recommendation was brought about by two problem areas:

For example:

RNLDEF RNL(CON) TYPE(GENERIC)
QNAME(SYSZRMM)
RNAME(MASTER.RESERVE)