Db2 data sharing

In Db2 data sharing, applications that reside in multiple Db2 subsystems in a Parallel Sysplex can read from and write to the same Db2 for z/OS® data concurrently, with integrity, performance, scalability, and dynamic workload balancing.

Db2 subsystems that share data must belong to a Db2 data sharing group, which runs on a IBM® zSystems Parallel Sysplex® cluster. A data sharing group is a collection of one or more Db2 subsystems that access shared Db2 data.

A Parallel Sysplex is a cluster of z/OS systems that communicate and cooperate with each other. The Parallel Sysplex is a highly sophisticated cluster architecture. It consists of two key pieces of technology:

Coupling facility

Provides specialized hardware, specialized high-speed links and adapters, and a shared, nonvolatile electronic storage for fast intersystem data sharing protocols.

Sysplex Timer

Provides a common time source across all the systems in the cluster, thereby delivering an efficient way to provide log-record sequencing and event ordering across the different systems.

The coupling facility and the Sysplex Timer are exclusive to the IBM zSystems environment. They provide strong performance and scalability in a multisystem clustered DBMS environment with shared disks.

Each Db2 subsystem that belongs to a particular data sharing group is a member of that group. All members of a data sharing group use the same shared Db2 catalog.

You can use some capabilities that are described in this information regardless of whether you share data. The term data sharing environment refers to a situation in which a data sharing group is defined with at least one member. In a non-data-sharing environment, no group is defined.