Checking hardware configuration and settings
- Optimize disk speed
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.
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 used for the database log files reduces disk contention and improve throughput.
Recommendation: Use disk I/O subsystems 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
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.
In the absence of other bottlenecks, increasing the processing power can improve throughput, response times, or both. On WAS for IBM i, processing power can be related to the Commercial Processing Workload (CPW) value of the system.
- Increase system memory
Increase memory to prevent the system from paging memory to the disk to improve performance. Allow a minimum of 256 B 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 the configuration is optimal.
Use 256 MB of memory for each processor and 512 B per application server. Some applications might require more memory.
- 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.
Verify the highest speed is in use on 10/100/1000 Ethernet networks.
To maximize performance, use a fast DASD subsystem (for example, IBM Shark), running with a high cache read/write hit rate.bprac
For high bandwidth applications, use at least a 1 Gb Ethernet connection. If the applications have extremely high bandwidth requirements, you may need additional Ethernet connections.bprac