  Mixed version cluster? (V5.5-2H4 and V7.1) 
 The Question is:
 
BACKGROUND
We have a cluster which comprises of two VAX 4000-150A sharing disks thru
DSSI. Both nodes run OpenVMS 5.5-2H4. The cluster may be seen as a black box
where an application runs on one of the nodes - the other node being used in
case of problems on the fir
st node.
The shared disks are spread equally over two Storage Works and only one half
is ever used for the live production machine at a time.
 
OBJECTIVE
To upgrade; OpenVMS to 7.1 and the application (supplied by a third party)
to be compatible with OpenVMS 7.1 and address Y2K issues. This within a
timespan of 6 to 8 months.
 
QUESTION
Is it technically possible to have this cluster with one node on 5.5-2H4 and
the other on 7.1 ?
 
I have read the SPD's for both cluster versions of OpenVMS and warrented
support not offered for such a mixed cluster. Does this mean that it is not
technically possible or that it is just not supported?
 
Thanks in advance
 
Trevor Owens
 
 
 The Answer is:
 
  Please see the OpenVMS and OpenVMS Cluster Software Product Descriptions
  (SPDs) for the "warranted" and "migration" support configurations.
 
  Supported configuration information is generally derived from a knowledge
  that a particular configuration does not work, or from a lack of knowledge
  due to the lack of sufficient testing.  Specific identification of the
  reason(s) is not generally provided.
 
  The Wizard is aware of customer sites that have strayed beyond the
  supported cluster configuration requirements, with varying results.
  The Wizard would obviously tend not to recommend this configuration,
  and would particularly not recommend this configuration where products
  such as volume shadowing, disk defragmenters, or similar were in use.
 
  All management of DECnet proxies and such will likely have to occur
  on the V7.1 node -- when configurations including older releases as
  well as OpenVMS VAX V6.1 or later or OpenVMS Alpha V6.2 are in use,
  DECnet proxy management should always be from the OpenVMS VAX V6.1 or
  later or the OpenVMS Alpha V6.2 or later node(s).
 
  V7.1 and later do include a new MOUNT utility and related new support,
  there is a compatibility kit available for OpenVMS V6.2 releases -- the
  new release is expected to be compatible with the older versions such
  as the original V6.2 version, but the older versions are known to have
  problems that the new version corrects.  No similar kit is available for
  releases prior to V6.2.
 
  NB: Though the Wizard does not wish to discourage the upgrade, the Wizard
  must note that a Y2K Readiness kit is available for OpenVMS VAX V5.5-2H4.
 
