The Adaptec 1742A SCSI controller used in the DEC 2000 model 300 does
not support the capabilies necessary for clustering via SCSI. Also
note Adaptec has retired this particular controller.
The DEC 2000 model 300 systems can be clustered via NI. Or via FDDI
(it has an EISA bus, so it can use the DEFEA FDDI adapter).
According to the OpenVMS Cluster Software, Version 6.2 SPD; both the
AlphaServer 2000 and the AlphaServer 400 systems support clustering
using SCSI. Only the embedded SCSI adaptor or a KZPAA can be used for
the multihost SCSI. The multihost SCSI can include DWZZA and even
HSZ40-B controllers. No tapes, floppies, nor CD-ROMs are permitted on
the multihost SCSI.
Don't confuse the AlphaServer 2000 (which is supported in SCSI clusters)
with the DEC 2000 Model 300 (which is not supported).
and of course now with OpenVMS Alpha V6.2-1H1 you can also use SCSI
clustering over FWD (i.e. KZPSA). Check the SPD for detailed and
supported configs.