scsi_maxphys(5)                                             scsi_maxphys(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      scsi_maxphys - maximum allowed length of an I/O on all SCSI devices

 VALUES    [Toc]    [Back]
    Failsafe
      1048576

    Default    [Toc]    [Back]
      1024*1024

    Allowed values    [Toc]    [Back]
      1048576 (16777215 and 33554432 for V-Class systems)

    Recommended values    [Toc]    [Back]
      1048576 (16777215 for V-Class systems)

 DESCRIPTION    [Toc]    [Back]
      This tunable sets the maximum data size the SCSI subsystem will accept
      for an I/O.  Depending on the device's characteristics and the device
      driver configuration, the maximum size allowed by the SCSI subsystem
      for a particular SCSI device might be lower than or equal to this
      tunable's value.  It will never be greater.

    Who Is Expected to Change This Tunable?
      Any customer.

    Restrictions on Changing    [Toc]    [Back]
      Changes to this tunable will take effect when the device is first
      opened.

    When Should the Value of This Tunable Be Raised?
      The value should never be raised except on V-Class systems where it
      can be raised to 32 MB.

    When Should the Value of This Tunable Be Lowered?
      The value should never be lowered.

    What Other Tunables Should Be Changed at the Same Time as This One?
      None.

 WARNINGS    [Toc]    [Back]
      All HP-UX kernel tunable parameters are release specific.  This
      parameter may be removed or have its meaning changed in future
      releases of HP-UX.

      Installation of optional kernel software, from HP or other vendors,
      may cause changes to tunable parameter values.  After installation,
      some tunable parameters may no longer be at the default or recommended
      values.  For information about the effects of installation on tunable
      values, consult the documentation for the kernel software being
      installed. For information about optional kernel software that was



 Hewlett-Packard Company            - 1 -      HP-UX 11i Version 2: Sep 2004






 scsi_maxphys(5)                                             scsi_maxphys(5)
                          Tunable Kernel Parameters



      factory installed on your system, see HP-UX Release Notes at
      http://docs.hp.com.

 AUTHOR    [Toc]    [Back]
      scsi_maxphys was developed by HP.


 Hewlett-Packard Company            - 2 -      HP-UX 11i Version 2: Sep 2004