Promise Technology VTrack M-Class M200i - Manual (Page 300)

VTrak M-Class Product Manual
292
Connection Problems
When you install your Promise product following the instructions in the Quick
Start Guide and this Product Manual, you should have little trouble getting your
equipment to work the first time. But connection problems can arise that are not
the User's or Installer's fault. Every conceivable problem cannot be covered in
the documentation but some guidelines could be helpful.
Connection problems cause a majority of failures in almost any electrical system.
While the installation of the cables and components was correct, they don't
function properly, or at all, because:
• A connector is dirty or corroded
• A connector is loose or damaged
• A cable looks OK outside but has an open circuit inside
• The wrong cable was used
VTraks ship with a full set of new cables, as required for each specific model. Be
sure to use these components because: 1.) They are the proper ones for your
RAID subsystem, 2.) They are in brand-new condition, and 3.) You paid for them
with the purchase of your VTrak.
SCSI Connections
VTrak uses a network connection to pass command and management
information. Data is transmitted via the SCSI bus. Proper termination and SCSI-3
compliant cables are required for the system to operate correctly.
SCSI connections are both physical (outside) and electrical (inside). You can see
a physical connection, you can clean it or try a different cable on it. Electrical
connections are made by firmware and software.
VTrak makes use of SCSI Target IDs (TIDs) and Logical Unit Numbers (LUNs) to
enable multiple VTrak arrays managed by a single Host PC
SCSI channels are completely intolerant of TID conflicts. If you have a conflict,
the devices on your SCSI chain will not work correctly until it is resolved.
The VTrak RAID subsystem is sensitive to the presence of other devices on the
SCSI chain. Do not connect other devices to the SCSI chain with a VTrak, except
for an other VTrak.
Termination
VTrak has an internal termination feature but it works only on the “Out”
connector. Internal termination is set to “Automatic” by default. For termination
settings, see “SCSI Channel Settings” on page 95 or “Channel Settings” on
page 198.