2.1 Scalability considerations
To reduce cost and increase efficieny, On demand computing requires the ability to scale an application up or down, depending on current requirements. This section discusses scalability strategies using WebSphere Application Server to help ensure high availability, load balancing, and the removal of bottlenecks.
The basic infrastructure components that comprise a WebSphere application are:
- Web server and Web server plug-in
- Web container
- EJB container
- Databases
WAS implements Web containers and EJB containers in each appserver. Each appserver runs in its own JVM.
If all components are co-located on a single LPAR, they might compete for LPAR resources, influence each other's behavior, or have unauthorized access to strategic resources.
Scaling strategies include, in general order of effectiveness...
- Clustering appservers
- Using a faster machine
- Creating a cluster of LPARs
- Using appliance servers
- Segmenting the workload
- Batch requests
- Aggregating
- Managing connections
- Cachings
See also:
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