STRMSGSZ(5)                                                     STRMSGSZ(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      STRMSGSZ - maximum size of streams message data (bytes)

 VALUES    [Toc]    [Back]
    Failsafe
      0

    Default    [Toc]    [Back]
      0

    Allowed values    [Toc]    [Back]
      0 - 2147483647

    Recommended values    [Toc]    [Back]
      0

 DESCRIPTION    [Toc]    [Back]
      This tunable limits the number of bytes of message data that can be
      inserted by putmsg() or write() in the data portion of any streams
      message on the system.  If the tunable is set to zero, there is no
      limit on how many bytes can be placed in the data segment of the
      message.

      putmsg() returns [ERANGE] if the buffer being sent is larger than the
      current value of STRMSGSZ; write() segments the data into multiple
      messages.

    Who Is Expected to Change This Tunable?
      Any customer.

    Restrictions on Changing    [Toc]    [Back]
      Changes to this tunable take effect at next reboot.

    When Should the Value of This Tunable Be Raised?
      The tunable should be increased by any customer if the customer's
      STREAMS module/driver(s) require a longer message size in the data
      portion than the current value.

    What Are the Side Effects of Raising the Value of This Tunable?
      The kernel will use more memory.  During low memory situations, it may
      bring down system performance due to frequent swapping.

    When Should the Value of This Tunable Be Lowered?
      The tunable could be lowered by any customer if the customer's STREAMS
      module/driver(s) do not require a longer message size in the data
      portion than the current value.

    What Are the Side Effects of Lowering the Value of This Tunable?
      Possible improper functioning in any of the STREAMS module/driver(s).
      Possible performance degradation, particularly in networking.




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






 STRMSGSZ(5)                                                     STRMSGSZ(5)
                          Tunable Kernel Parameters



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

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


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