Network Deployment (Distributed operating systems), v8.0 > Reference > Tune tips
Tune parameter hot list
The following hot list contains recommendations that have improved performance or scalability, or both, for many applications.
WAS provides several tunable parameters and options to match the application server environment to the requirements of the application.
- Review the hardware and software requirements
It is critical for proper functionality and performance to satisfy the minimum hardware and software requirements. Refer to IBM WAS supported hardware, software, and APIs website which details hardware and software requirements.
- Install the most current refresh pack, fix pack, and the recommended interim fixes
The list of recommended updates is maintained on the Support site.
- Check hardware configuration and settings
Verify network interconnections and hardware configuration is setup for peak performance.
- Tune the operating systems
Operating system configuration plays a key role in performance. For example, adjustments such as TCP/IP parameters might be necessary for the application
- Set the minimum and maximum JVM heap sizes
Many applications need a larger heap size then the default for best performance. It is also advised to select an appropriate GC policy based on the application's characteristics.
- Use a type 4 (or pure Java) JDBC driver
In general, the type 2 JDBC driver is recommended if the database exists on the same physical machine as the WebSphere instance. However, in the case where the database is in a different tier, the type 4 JDBC driver offers the fastest performance since they are pure Java not requiring native implementation. Use the link above to view a list of database vendor-specific requirements, which can tell you if a type 4 JDBC driver is supported for your database.
- Tune WAS JDBC data sources and associated connection pools
The JDBC data source configuration might have a significant performance impact. For example, the connection pool size and prepared statement cache need to be sized based on the number of concurrent requests being processed and the design of the application.
See the Connection pooling topic for more information.
- Enable the pass by reference option
Use applications that can take advantage of the pass by reference option to avoid the cost of copying parameters to the stack.
- Ensure that the transaction log is assigned to a fast disk
Some applications generate a high rate of writes to the transaction log. Locating the transaction log on a fast disk or disk array can improve response time.
- Tune related components, for example, database
In many cases, some other component, for example, a database, needs adjustments to achieve higher throughput for your entire configuration.
- Disable functions that are not required
For example, if the application does not use the web services addressing (WS-Addressing) support, disabling this function can improve performance.
Attention: Use this property with care because applications might require WS-Addressing MAPs to function correctly. Setting this property also disables WAS support for the following specifications, which depend on the WS-Addressing support: Web Services Atomic Transactions, Web Services Business Agreement and Web Services Notification.
To disable the support for WS-Addressing, refer to Enable Web Services Addressing support for JAX-RPC applications
- Review the application design
We can track many performance problems back to the application design. Review the design to determine if it causes performance problems.
Tune the application serving environment
Task overview: Using the dynamic cache service to improve performance
Use application clients
Related
Tune TCP/IP buffer sizes
IBM eServer Workload Estimator