  OpenVMS Cluster Compatibility, Considerations? 
 The Question is:
 
I have been asked to propose a way of replacing the disks that exist in a
cluster comprising of a VAX 4500 and two m3100 systems. Current disks are a
mixture of scsi and dssi with all systems mounting all disks within the
cluster. I thought that a small a
lpha using a storage array would provide a good platform to mscp serve disks
the cluster.
What implications are there for a cluster running 5.5-2 if a new node was
added running a much newer vms version ? The new node would only serve disks
and would not participate in the cluster in any other way.
 
 
 The Answer is:
 
  You will need a second system disk -- OpenVMS Cluster configurations
  can have one or more system disks, and OpenVMS Cluster configurations
  with a mixture of VAX and Alpha systems will have two or more system
  disks.
 
  You will be limited to 8.5 GB disk volumes or smaller, due to limits
  present in all OpenVMS VAX releases prior to V6.0 -- please see the
  discussion in the OpenVMS Frequently Asked Questions (FAQ) for some
  further details.
 
  There is no "partial" participation of a member in an OpenVMS Cluster,
  all nodes are full members.  Nodes may or may not share system disks
  or serve disks or tapes, but all member nodes are full members.
 
  You will need to operate with a version of OpenVMS Alpha that is
  compatible with the locally-required release of OpenVMS VAX, or
  you will need to upgrade the OpenVMS VAX systems to a more recent
  OpenVMS release.
 
  There are a few minor restrictions around such things as SYSMAN use,
  as older SYSMAN implementations do not know how to communicate with
  newer SYSMAN -- though newer SYSMAN can communicate with older SYSMAN.
  You will also want to ensure that all account and system management
  is performed from OpenVMS VAX V6.1 or later or from OpenVMS Alpha V6.2
  or later, if these or later versions are configured.  Additional
  information is in the OpenVMS release notes and new features manuals.
 
  When choosing an OpenVMS Alpha system for this configuration, remember
  to compare the minimum OpenVMS Alpha supported release for the system
  with the OpenVMS Cluster release compatibility matrix, to ensure that
  the system can coexist in an OpenVMS Cluster with the existing OpenVMS
  versions -- unless an upgrade is feasible.
