Compaq TruCluster Server AA-RHGWB-TE, Manual

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2.8 DS-DWZZH-03 and DS-DWZZH-05 UltraSCSI Hubs
The DS-DWZZH-03 and DS-DWZZH-05 series UltraSCSI hubs are the only
hubs supported in a TruCluster Server configuration. They are SCSI-2-
and draft SCSI-3-compliant SCSI 16-bit signal converters capable of data
transfer rates of up to 40 MB/sec.
These hubs can be listed with the other SCSI bus signal converters, but as
they are used differently in cluster configurations they will be discussed
differently in this manual.
A DS-DWZZH-03 or DS-DWZZH-05 UltraSCSI hub can be installed in:
• A StorageWorks UltraSCSI BA356 shelf (which has the required
180-watt power supply).
• The lower righthand device slot of the BA370 shelf within the RA7000
or ESA 10000 RAID array subsystems. This position minimizes cable
lengths and interference with disks.
• A wide BA356 which has been upgraded to the 180-watt power supply
with the DS-BA35X-HH option.
A DS-DWZZH-03 or DS-DWZZH-05 UltraSCSI hub:
• Improves the reliability of the detection of cable faults.
• Provides for bus isolation of cluster systems while allowing the remaining
connections to continue to operate.
• Allows for more separation of systems and storage in a cluster
configuration, because each SCSI bus segment can be up to 25 meters
in length. This allows a total separation of nearly 50 meters between
a system and the storage.
______________________ Note _______________________
The DS-DWZZH-03/05 UltraSCSI hubs cannot be connected to a
StorageWorks BA35X storage shelf because the storage shelf does
not provide termination power to the hub.
2.9 SCSI Cables
If you are using shared SCSI buses, you must determine if you need
cables with connectors that are low-density 50-pins, high-density 50-pins,
high-density 68-pins (HD68), or VHDCI (UltraSCSI). If you are using an
UltraSCSI hub, you will need HD68 to VHDCI and VHDCI to VHDCI cables.
In some cases, you also have the choice of straight or right-angle connectors.
Hardware Requirements and Restrictions 2–9