HP OpenVMS Systems

Serving SCSI tapes in Cluster? (TMSCP)

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The Question is:

 
We have two AlphaServer 1200's in a SCSI cluster,
each with an exabyte tape drive connected to the
local SCSI bus.
 
Whilst it is not a problem accessing these
devices via queues, is it possible to share
these tape devices to other nodes in the cluster
for interactive use. If so how ?
 

The Answer is :

 
  OpenVMS does not permit tape devices connected onto a multi-host SCSI bus.
  This restriction is a result of the expected incidence of SCSI bus resets
  on the shared bus -- SCSI tape devices and various other SCSI widgets do
  not tolerate these bus resets in a re-entrant fashion.
 
  OpenVMS does permit TMSCP services for SCSI tape devices, meaning that
  most locally-connected SCSI tape drives -- as well as more traditional
  tape devices accessed by the TMSCP protocols -- can be served to other
  nodes in the cluster.
 
  For information on serving devices, please see:
 
http://www.openvms.digital.com:8000/72final/4477/4477pro_010.html#mscp_disks
 
  As for whether or not a particular third-party SCSI tape drive will
  operate via TMSCP services, please contact the vendor or the integrator
  for assistance.
 
	--
 
  Note: all OpenVMS Clusters with multi-host SCSI can have -- must have --
  one or more additional communications interconnect(s) configured.  It is
  not permitted to have an OpenVMS Cluster with only a SCSI interconnect.
 

  

     

     
answer written or last revised on ( 5-MAY-1999 )
     
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