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OpenVMS and disk I/O queue depth?

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The Question is:

I have a raid5 device connected to a ultra-scsi adapter (differential)on a
 alpha-server 1200, running VMS 7.1-2. My question is : How can I modify the
 queue_depth parameter in VMS. When the same raid5 disk is connected to for ex)
 a solaris host, then this
 is modified in the solaris system file.
Many thanks and best regards,

The Answer is :

  OpenVMS normally queries the storage device and figures out what
  it is capable of.  In the case of tagged command queuing (TCQ),
  OpenVMS Alpha uses what the reports its capabilities as.
  OpenVMS itself also has a concept of "queue depth", a value derived
  from the number of I/O operations outstanding to a particular device.
  This is not a configurable setting.
  Please contact the hardware support organization for the particular
  local configuration, as you will need to specifically identify the
  RAID controller and the UltraSCSI adapter involved, as well as the
  management software (if any) for the interface.
  When posting to the Ask The Wizard website, please remember to
  include specifics, as well as some background (general) details of
  the problem(s) you are trying to solve -- are you seeing an I/O
  performance problem here, for instance?

answer written or last revised on ( 21-MAR-2000 )

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