The Question is:
Does a VAX 4000 DSSI cluster need to be connected via a network as well as DSSI?
In other words could a 2 node DSSI cluster operate on different networks?
The Answer is :
An OpenVMS Cluster using a DSSI interconnect does not need an addition
cluster communications interconnect such as an Ethernet or FDDI network
connection, as long as at least one DSSI bus directly connects each
memory of the cluster, and as long as no cluster member depends (solely)
on the KFQSA adapter -- the KFQSA is a storage-only Q-bus adapter and
does not permit host-to-host SCS communications nor clustering.
Cluster SCS traffic can use the DSSI bus.
Note that if you do not have a common network interconnect, you lose an
important availability feature: if the DSSI connection fails for any
reason, your cluster will hang (due to quorum lost) until it is repaired.
With a network connection, SCS traffic will fail over to the network.
The DSSI configuration will work, and without a network connection.