Data Sharing Benefits
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| DB2 data sharing, though somewhat complex to implement and administer, provides many benefits. In the long run, most organizations will move to DB2 data sharing because of the many benefits outlined in this section. The primary benefit of data sharing is to provide increased availability to data. DB2 data sharing provides a powerful technology for solving complex business problems in an optimal manner. Data is available for direct access across multiple DB2 subsystems. Furthermore applications can be run on multiple smaller, more competitively priced microprocessor-based machines, thereby enhancing data availability and the price/performance ratio. An additional benefit is expanded capacity. Capacity is increased because more processors are available to execute the DB2 application programs. Instead of a single DB2 subsystem on a single logical partition, multiple CPCs can be used to execute a program (or even a single query). Each data sharing group may consist of multiple members; application programs are provided with enhanced data availability. There is no primary or "owner" DB2 subsystem. All DB2 subsystems in a data sharing group are peers. One or more members of a group may fail without impacting application programs because the workload will be spread across the remaining DB2 members . Therefore, failure of one DB2 subsystem cannot cause the other subsystems to become unavailable. Data sharing increases the flexibility of configuring DB2. New members can be added to a data sharing group when it is necessary to increase the processing capacity of the group (for example, at month end or year end to handle additional processing). The individual members that were added to increase the processing capacity of the data sharing group are easily removed when it is determined that the additional capacity is no longer required. Finally, prior to data sharing, larger organizations with multiple MVS machines often devoted individual processors to groups of users. When a DB2 application needed to span the organization, it was usually necessary to create a duplicate copy of the application for each DB2 on each system image used by the organization. With data sharing, a single data sharing group can be created for the entire organization (within the limit of 32 subsystems per group). This can alleviate the need to create multiple copies of an application. What Are Sysplex and Parallel Sysplex?A Sysplex is a set of OS/390 images that are connected and coupled by sharing one or more Sysplex timers. A Parallel Sysplex is a basic Sysplex that additionally shares a Coupling Facility whose responsibility is to provide external shared memory and a set of hardware protocols that allow enabled applications and subsystems to share data with integrity by using external shared memory. Parallel Sysplex enhances scalability by extending the ability to increase the number of processors within a single OS/390 image with the ability to have multiple OS/390 images capable of cooperatively processing a shared workload. Additionally, Parallel Sysplex enhances availability by providing customers with the ability to non-disruptively remove one or more OS/390 images and/or CECs from a configuration to accommodate hardware and software maintenance. Consider obtaining and reviewing the following IBM manuals and redbooks before learning more about the Parallel Sysplex:
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EAN: 2147483647
Pages: 388