Summary for the WebSphere Application Server performance tests

Edit online

After running the WebSphere Application Server performance tests on our test environment, we compiled a summary of our results and recommendations.

Our test results and recommendations are specific to our environment. Parameters useful in our environment might be useful in other environments, but are dependent on application usage and system configuration. You will need to determine what works best for your environment. For our detailed test results information, see Results for the WebSphere Application Server performance tests.

The following are our summary results:
  • WebSphere® Application Server version 6.1 (31-bit) has a significant advantage compared to version 6.0.2. This advantage seems to be a result of successful optimization leading to higher throughputs at lower cost. The change from 6.0.2 to 6.1 (31-bit) can be highly recommended.
  • Sharing one network card for all traffic was identified as a bottleneck. Using a separate network card for the traffic to the client and another for the traffic to the database results in a very good ETR improvement of 27%.
  • The modification of the logging setup from the database on Linux® showed that many smaller log files gave better throughputs than a reduced number of large log files. Note that we did not consider recovery performance in this paper.
  • We identified some database structures (indexes, data types, code page conversion) from the database setup of DB2® on z/OS® that could be optimized. Changing the z/OS database setup gave a throughput improvement of 12%.
  • The I/O feature asynchronous I/O (AIO) on WebSphere has an advantage with both databases. Because, in our case, WebSphere Application Server does very little disk I/O, the advantage comes from doing asynchronous network I/O.
  • Using a higher number of client systems to generate the workload did not improve the throughput.
  • For the environment with the database on z/OS, the upgrade from DB2 v8 to DB v9 has no affect on performance. For the environment with the database on Linux, the message is not that simple. The new version is better optimized, which indicates a reduced CPU utilization, but the total throughput is slightly decreased. So, DB2 v9 on Linux has a lower cost per transaction. This yields an increase in ITR with a slight decrease in ETR.
  • The upgrade of the WebSphere Application Server system to SLES10 leads to a slight decrease in throughput at the same CPU cost with the database on z/OS. With the database on Linux, the throughput decrease is less and the cost increases.
  • Switching a WebSphere 6.1 environment from 31-bit to 64-bit addressing uses additional CPU and storage resources. Therefore, using 64-bit mode can only be recommended if the application needs more than 31-bit addressing to accomplish its function. Further investigations are required to show what throughputs can be reached using a 64-bit WebSphere Application Server in an environment that requires 64-bit support.
  • In general, the use of HiperSockets can be highly recommended. HiperSockets has much lower latencies, because it is implemented in memory. This results in much higher network throughput, but HiperSockets have higher CPU costs because no work is off-loaded to the OSA Express card, which results in a lower internal throughout. Systems running at high CPU utilization might not benefit from the use of HiperSockets.