Hardware capacity and configuration

These parameters include considerations for selecting and configuring the hardware on which the application servers can run:

• Disk speed
  Disk speed and the number of disk arms can have a significant effect on application server performance in these cases:
  • Your application is heavily dependent on database support
  • Your application uses messaging extensively
  In these situations, it is recommended that you use disk I/O subsystems that are optimized for performance, such as a RAID array. Distribute the disk processing across as many disks as possible to avoid contention issues that typically occur with 1 or 2 disk systems. For more information about disk arms and how they can affect performance, see iSeries Disk Arm Requirements.

• Processor speed
  In the absence of other bottlenecks, increasing the processing power can improve throughput, response times, or both. On iSeries, processing power can be related to the Commercial Processing Workload (CPW) value of the system. For more information about CPW values, see the Performance Capabilities Reference Manual in the Performance Management Resource Library.

• System memory
  If a large number of page faults occur, performing these tasks might improve performance:
  • Increase the memory available to WebSphere Application Server - Express.
  • Move WebSphere Application Server - Express to another memory pool.
  • Remove jobs from the WebSphere Application Server - Express memory pool.
  To determine the current page fault level, run the Work with System Status (WRKSYSSTS) command from the CL command line. For information about the minimum memory requirements, see iSeries and AS/400 hardware requirements in the Installation topic.

• Storage pool activity levels
  Verify that the activity levels for storage pools are sufficient. Increasing these values can prevent threads from transitioning into the ineligible condition.
  • To modify the activity level for the storage pool in which you are running WebSphere Application Server - Express, run the Work with System Status (WRKSYSSTS) command from the CL command line:

    WRKSYSSTS ASTLVL(*INTERMED)

  • Set the system value QMAXACTLVL to a value equal to or greater than the total activity level for all pools, or *NOMAX.
    1. Run the Work with System Value (WRKSYSVAL) command from the CL comand line:

       WRKSYSVAL SYSVAL(QMAXACTLVL)

    2. Adjust the value in the Max Active column.

• Networks
  Run network cards and network switches at full duplex. Running at half duplex decreases performance. Verify that the network speed can accommodate the required throughput. On 10/100 Ethernet networks, verify that 100MB is in use. You might also want to monitor the IOP utilization. For information about IOP utilization, see the Performance Capabilities Reference in the Performance Management Resource Library.