tcphashsz(5)                                                   tcphashsz(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      tcphashsz - determines the size of the networking hash tables

 VALUES    [Toc]    [Back]
    Failsafe
      2048

    Default    [Toc]    [Back]
      2048

    Allowed values    [Toc]    [Back]
      256 to 65536

    Recommended values    [Toc]    [Back]
      2048

      Specify as a power of two or it will be rounded down to the nearest
      power of two.

 DESCRIPTION    [Toc]    [Back]
      This variable is used to set the size of the networking hash tables.
      A system that is going to have a large number of connections on it all
      of the time may see some benefit of increasing this value.

      This tunable needs to be a power of two.  If it is not specified as a
      power of two, then it is rounded down to the nearest power of two.

    Who Is Expected to Change This Tunable?
      Anyone.

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

    When Should the Value of This Tunable Be Raised?
      This value may be raised in the case of a machine with a large number
      of connections that last for an extended period of time.

    What Are the Side Effects of Raising the Value?
      More memory is used when this value is raised.

    When Should the Value of This Tunable Be Lowered?
      If a system is tight on memory and it has just a few connections on
      it, then lowering the value may reclaim some memory.

    What Are the Side Effects of Lowering the Value?
      If set too low, the system will have long hash chains which will slow
      it down.

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




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






 tcphashsz(5)                                                   tcphashsz(5)
                          Tunable Kernel Parameters



 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]
      tcphashsz was developed by HP.


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