Checking hardware configuration and settings

An optimal hardware configuration enables applications to get the greatest benefit from performance tuning. The hardware speed impacts all types of applications and is critical to overall performance.

Overview

For proper system sizing for WebSphere Application Server workloads, use the IBM Systems Workload Estimator.

The following parameters include considerations for selecting and configuring the hardware on which the application servers run.

Procedure

• Optimize disk speed
  • Description: Disk speed and the number of disk arms have a significant effect on application server performance in the following cases:

    • Your application is heavily dependent on database support .

    • Your application uses messaging extensively.

  • Recommendation: Use disk I/O subsystems that are optimized for performance, for example, Redundant Array of Independent Disks (RAID). Distribute the disk processing across as many disks as possible to avoid contention issues that occur with 1 or 2 disk systems. For more information about disk arms and how they can affect performance, see the iSeries Disk Arm Requirements documentation.

• Increase processor speed and processor cache
  • Description: In the absence of other bottlenecks, increasing the processing power can improve throughput, response times, or both. On WebSphere Application Server for i5/OS, processing power can be related to the Commercial Processing Workload (CPW) value of the system. For more information about CPW values, see the http://www.ibm.com/servers/eserver/iseries/perfmgmt/resource.html Web site.

• Increase system memory
  • Description: If a large number of page faults occur, performing the following tasks to improve performance:

    • Increase the memory available to WebSphere Application Server.

    • Move WebSphere Application Server to another memory pool.

    • Remove jobs from the WebSphere Application Server memory pool

  • Recommendation: To determine the current page fault level, run the Work with System Status (WRKSYSSTS) command from an i5/OS command line. For information about the minimum memory requirements, see the IBM Support Web site.

• Run network cards and network switches at full duplex

  • Description: Run network cards and network switches at full duplex and use the highest supported speed. Full duplex is much faster than half duplex. Verify that the network speed of adapters, cables, switches, and other devices can accommodate the required throughput. Some Web sites might require multiple gigabit links.

  • Recommendation Verify the highest speed is in use on 10/100/1000 Ethernet networks.

  Verify that the activity levels for storage pools are sufficient

  • Description: Verify that the activity levels for storage pools are sufficient. Increasing these values can prevent threads from transitioning into the ineligible condition.

  • Recommendation

    • To modify the activity level for the storage pool in which you are running WebSphere Application Server, run the following WRKSYSSTS command from the command line:

      WRKSYSSTS ASTLVL(*INTERMED)

    • Perform the following steps to set the QMAXACTLVL system value to a value equal to or greater than the total activity level for all pools, or *NOMAX:

      • Run the following WRKSYSSTS command from the command line:

        WRKSYSSTS ASTLVL(*INTERMED)

      • Adjust the value in the Max Active column.