Target-oriented workload management with WebSphere application Server for z/OS

In addition to providing Best-in-class j2ee™ application runtimes on top of the IBM System z™ platform, ibm®websphere®application Server for z/os® is optimized to take advantage of Sy, the core engine of today's enterprise SOA environment Stem Z's unique technical advantages. One of the most important unique features of WebSphere application Server for z/OS is the goal-oriented workload management feature.

Introduction

The Java EE server running on z/OS is implemented by multiple address spaces or processes. There is a control area, at least one service area, and one (or none) control area Adjunct, as shown in Figure 1.

The control zone is used to accept client requests (HTTP, IIOP) and to classify requests into different service categories based on predefined rules. For example, HTTP requests are categorized based on different URLs, providing the ability to set target service levels for different application components deployed on the same application server. After the workload classification is completed, the control area inserts the request into the queues managed by IBM Workload Manager (WLM) for z/OS. The service area picks up the requests from these queues and processes the requests in the service area address space.

The control area is controlled by the user, which means that you can use the command to start or stop the control area. The user does not directly control the service area. Instead, WLM dynamically starts and maintains the service area as needed to meet the performance goals of the workload. IBM WebSphere Application Server uses the WLM Queue Manager service to maintain queues, passing requests from the control zone to the service area. There will be more discussion on this later. For the purposes of this article, it is not important to control regional Adjunct, so no further discussion will be made. ）

Figure 1. WebSphere application Server for z/OS architecture

Before studying the details of this configuration, let me first list some of the reasons why the WebSphere application Server for z/OS uses the split address space architecture:

Business-oriented workload management:

The architecture provides the ability to differentiate between higher-priority queries (for example, completing 95% in 0.05 seconds) and lower-priority queries (for example, completing 80% in 5 seconds).

WLM can dynamically manage the number of service areas to achieve overall system throughput objectives.

Detach transaction with Application execution:

Trusted code runs in the control area, and user application code runs in the service zone, which completely isolates application execution from transaction management.

Transaction recovery is handled by the control area.

The WebSphere Application Server provides additional exception handling mechanisms. For example, transaction timeout: When a transaction timeout is detected in the control zone, the control zone can be set to restart the service area to clean up system resources, preventing the resource from being blocked by application hangs.

The remainder of this article will examine the integration of WebSphere application Server for z/OS and workload Manager for z/Os in detail.