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.

About this task

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

You can check hardware configuration and settings such as disk speed, system memory and processor speed to gain performance benefits.

Procedure

  • Use the following considerations for selecting and configuring the hardware on which the application servers run:
    1. Optimize disk speed
      [AIX Solaris HP-UX Linux Windows][z/OS]
      • Description: Disk speed and configuration have a dramatic effect on the performance of application servers running applications that are heavily dependent on the database support, using extensive messaging, or processing workflow. The disk input or output subsystems that are optimized for performance, for example Redundant Array of Independent Disks (RAID) array, high-speed drives, and dedicated caches, are essential components for optimum application server performance in these environments.

        Application servers with fewer disk requirements can benefit from a mirrored disk drive configuration that improves reliability and has good performance.

      • Recommendation: Spread the disk processing across as many disks as possible to avoid contention issues that typically occur with 1- or 2-disk systems. Placing the database tables on disks that are separate from the disks that are used for the database log files reduces disk contention and improve throughput.
      [IBM i]
      • 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.
    2. Increase processor speed and processor cache
      • [AIX Solaris HP-UX Linux Windows][z/OS]Description: In the absence of other bottlenecks, increasing the processor speed often helps throughput and response times. A processor with a larger L2 or L3 cache yields higher throughput, even if the processor speed is the same as a CPU with a smaller L2 or L3 cache.
      • [IBM i]Description: In the absence of other bottlenecks, increasing the processing power can improve throughput, response times, or both. On WebSphere Application Server for IBM i, processing power can be related to the Commercial Processing Workload (CPW) value of the system.
    3. Increase system memory
      [z/OS]
      • Description: The amount of storage required for z/OS® is mostly dependent on the number of servers and the size of the Java™ Virtual Machine (JVM) heap for each server. If the system pages and the processor utilization is low because of the paging, adjust the available memory to improve performance.
      • Recommendation: In a multiple server environment, allow a minimum of 256 MB of memory for each processor and 512 MB per application server. In a single server environment with a 1 GB JVM heap, allocate a minimum of 1GB of memory. Some applications might require more memory.

        The memory access speed might depend on the number and placement of the memory modules. Check the hardware manual to make sure that your configuration is optimal.

      [AIX Solaris HP-UX Linux Windows]
      • Description: Increase memory to prevent the system from paging memory to the disk to improve performance. Allow a minimum of 256 MB of memory for each processor and 512 MB per application server. Adjust the available memory when the system pages and the processor utilization is low because of the paging. The memory access speed might depend on the number and placement of the memory modules. Check the hardware manual to make sure that your configuration is optimal.
      • Recommendation: Use 256 MB of memory for each processor and 512 MB per application server. Some applications might require more memory.
      [IBM i]
      • 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 IBM i command line. For information about the minimum memory requirements, see the IBM Support website.
    4. Increase system memory
      [z/OS]
      • Description: Increase memory to prevent the system from paging memory to the disk to improve performance. Allow a minimum of 256 MB of memory for each processor and 512 MB per application server. Adjust the available memory when the system pages and the processor utilization is low because of the paging. The memory access speed might depend on the number and placement of the memory modules. Check the hardware manual to make sure that your configuration is optimal.
      • Recommendation: Use 256 MB of memory for each processor and 512 MB per application server. Some applications might require more memory.
      [z/OS]
      • Description: The amount of storage required for z/OS is mostly dependent on the number of servers and the size of the Java Virtual Machine (JVM) heap for each server.
      • Recommendation: For a single server with 1 GB JVM heap, allocate a minimum of 1GB of memory.
      [AIX Solaris HP-UX Linux Windows]
      • Description: Increase memory to prevent the system from paging memory to the disk to improve performance. Allow a minimum of 256 MB of memory for each processor and 512 MB per application server. Adjust the available memory when the system pages and the processor utilization is low because of the paging. The memory access speed might depend on the number and placement of the memory modules. Check the hardware manual to make sure that your configuration is optimal.
      • Recommendation: Use 256 MB of memory for each processor and 512 MB per application server. Some applications might require more memory.
      [IBM i]
      • 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 IBM i command line. For information about the minimum memory requirements, see the IBM Support website.
    5. 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 websites might require multiple gigabit links.
      • Recommendation Make sure that the highest speed is in use on 10/100/1000 Ethernet networks.
    6. [IBM i]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.
    7. [z/OS]An IBM S/390® or zSeries Model that supports the software requirement of z/OS V1R2.
    8. [z/OS]Storage
      • Storage requirements are higher than for traditional workloads
      • Recommendation
        • Virtual storage default should be about 370 MB per servant, which includes a 256 MB default heap size and a default initial LE heap size of 80 MB.
        • Real storage minimum is 512 MB per LPAR for a light load such as the IVP. For most real-world applications, you should use 2 GB or higher. We have seen applications that require as much as 8 GB of real to operate at peak load.
  • [z/OS]DASD
    • Recommendation
      • To maximize your performance, you should use a fast DASD subsystem (for example, IBM Shark), running with a high cache read/write hit rate.
  • [z/OS]Networking
    • Recommendation
      • For high bandwidth applications, you should use at least a 1 Gb Ethernet connection. If your applications have extremely high bandwidth requirements, you may need additional Ethernet connections.
  • [z/OS]Cryptography
    • Recommendation
      • For applications that make heavy use of cryptography, you should use the zSeries or S/390 cryptographic hardware and the Integrated Cryptographic Service Facility. For more information, refer to Enterprise server solutions .