  Configuring OpenVMS Cluster interconnects? 
 The Question is:
 
Is it possible to cluster two AlphaServer 2000
with DSSI and SCSI busses used for cluster
interconnect ? Both busses must be active in
the cluster for data's migration.
 
thank you.
 
 
 The Answer is:
 
  Yes.  In an OpenVMS Cluster, you can configure as many interconnects
  as you like (and as your hardware will permit).
 
  There is one central requirement when configuring interconnects for
  an OpenVMS Cluster: each node within the cluster must be able to
  directly communicate with every other node in the cluster.  These
  intracluster communications can occur via any SCS-capable
  communications interconnect.  This requirement is also known as the
  "OpenVMS Cluster Rule of Total Connectivity".
 
  To meet the rule of total connectivity, most cluster configurations
  will use a broadcast connection such as CI, Ethernet, or FDDI.  This
  is the easiest to configure and to explain, but configurations with
  the correct organization of multiple cluster interconnects can also
  be used to meet the rule.
 
  The two most common interconnects used within clusters that are NOT
  capable of host-to-host SCS communications are storage interconnects.
  The two most common storage interconnects are SCSI and any KFQSA-based
  connection to a DSSI bus.  (DSSI connections via adapters other than
  the KFQSA can be used for host-to-host communications.)  These are
  storage interconnects, and do not permit host-to-host communications.
 
  As an example of using multiple interconnects to meet the rule of
  total connectivity: various configurations with DSSI daisy-chains
  are also possible.  Three hosts, each with two DSSI controllers,
  can be organized into a triangular configuration, with each of the
  two DSSI controllers present on each host connected to one of the
  adjacent hosts.  In other words, there are a total of three DSSI
  buses, and each DSSI bus has two hosts and zero or more storage
  devices or adapters connected to it.  (Most sites will also use an
  Ethernet or FDDI interconnect in this and in other configurations.)
 
