17.5.3 Hardware and capacity settings
Obviously, the hardware and its capacity play an important role in performance. Part 1 to Part 5 of this redbook provide detailed information about how to set up a scalable WebSphere environment. However, the following parameters are to be considered:
- Disk speed Disk speed and configuration can have a dramatic effect on the performance of appservers that run applications that are heavily dependent on database support, that use extensive messaging, or are processing workflow. Disk I/O subsystems that are optimized for performance, for example RAID array, are essential components for optimum appserver performance in these environments. It is recommended that you spread the disk processing across as many disks as possible to avoid contention issues that typically occur with one or two disk systems.
- Processor speed Increasing the processor speed often helps throughput and response times once other bottlenecks have been removed where the processor was waiting for such events as input and output, and application concurrency.
- System memory Increasing memory to prevent the system from paging memory to disk improves the performance. Allow a minimum of 256 MB of memory for each processor (512 MB is recommended). Adjust the parameter when the system is paging and processor utilization is low because of the paging.
- 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. Also, make sure that 100 MB is in use on 10/100 Ethernet networks.