Tuning HP-UX systems

This topic describes how to tune the HP-UX operating system to optimize the performance of your WebSphere® Application Server. Because the HP-UX operating system is not a WebSphere Application Server product, be aware that it can change and results vary

• Configure the following settings and variables according to your tuning needs:
  • Tuning the HP operating system with the DB2® type 2 JDBC driver
    When using the type 2 Java Database Connectivity (JDBC) driver on the HP operating system with DB2, you can increase the performance of WebSphere Application Server by preallocating the DB2 trace segment. Perform the following steps:

    1. Before starting application server, switch to the user that is associated with the DB2 instance.
    2. Run the db2trc alloc command.
    3. Start application server.

    Usage note: Use the type 4 driver for best performance and compatibility.

    Another issue with the type 2 JDBC driver on the HP operating system is code page conversion. Creating the database using the UTF-8 code set avoids this problem and significantly increases performance. See the database documentation for instructions on creating databases with a specific code set. Read the DB2 tuning parameters information.

  • The HP performance tuning parameters

    Modify HP-UX 11i settings to significantly improve WebSphere Application Server performance. For additional information about the HP performance tuning parameters, see the performance: resources for learning information.

  • Java virtual machine (JVM) virtual page size
    • Description: Sets the JVM instruction and data page sizes to 64 MB to improve performance.
    • How to view or set: Use the WASHOME/java/bin/SYSTEM_ARCH_PATH/java command. The command output provides the current operating system characteristics of the process executable.
    • Default value: 4 MB, if not assigned
    • Recommended value: 64 MB
  • HP-UX 11i TCP_CONN_REQUEST_MAX
    • Description: Specifies the maximum number of connection requests that the operating system can queue when the server does not have available threads. When high connection rates occur, a large backlog of TCP/IP connection requests builds up and client connections are dropped. Adjust this setting when clients start to time out after waiting to connect. Verify this situation by issuing the netstat -p tcp command. Look for the following value: connect requests dropped due to full queue
    • How to view or set: Set this parameter by using the ndd -set /dev/tcp tcp_conn_request_max 8192 command.
    • Default value: 4096
    • Recommended value: In most cases the default is sufficient. Consider adjusting this value to 8192, if the default proves inadequate.
  • HP-UX 11i kernel parameter recommendations

    Refer to the table of kernel parameters shown in the Preparing HP-UX systems for installation topic.

  • TCP_KEEPALIVE_INTERVAL
    • Description: Determines the interval between probes.
    • How to view or set: Use the ndd command to determine the current value or to set the value. For example:

      ndd -set /dev/tcp tcp_keepalive_interval 7200000

    • Default value: None
    • Recommended value: 7200000 milliseconds
  • TCP_KEEPALIVES_KILL
    • Description: Determines the maximum number of times to probe before dropping.
    • How to view or set: Use the ndd command to determine the current value or to set the value. For example:

      ndd -set /dev/tcp tcp_keepalives_kill 1

    • Default value: 1
    • Recommended value: 1
• 
  
  Keeping current with the operating system and Java patches is one of the most important things you can do to optimize the performance of a server. For the latest Java patches, visit the following website:

  HP-UX Patch Information

  Also, for the latest operating system quality pack, visit the following website:

  Support Plus: Quality Pack Bundles