Strategy for creating a Db2 data sharing group

When you create a data sharing group, add one member at a time. You can install a new Db2 for the first member (the originating member), or you can enable an existing Db2 subsystem as the originating member.

Before you begin

Familiarize yourself with the information in Planning for Db2 data sharing.

About this task

Enabling Db2 data sharing is a big step. Carefully plan your strategy because data sharing is difficult to disable after it is enabled. Disabling should only be considered if your long-term plans are to disable data sharing. During migration, test other major new capabilities in the new release on a single system before enabling data sharing, and then build and try a test data sharing group. When you are ready to begin a move to production, you must avoid having to fall back to the previous release.

Tip: Db2 target library and distribution library data sets can be shared among all members of a data sharing group. Sharing these libraries reduces the effort of installing and maintaining the different members of the data sharing group. Sharing libraries can also help ensure that members are using the same exit routines. Also, sharing libraries simplifies the tasks of defining a new member to a data sharing group. The member installation process supports sharing of the libraries.

Procedure

Follow this general strategy for creating a data sharing group:

  1. Build and try a test data sharing group. Here is one approach to testing your data sharing group:
    1. Install Db2 12 as a single system, and test it with dummy data, or copies of production data, in order to test some of the new capabilities. Run old applications and begin new application development work. In the meantime, prepare the hardware and define the coupling facility structures to enable data sharing.
    2. Enable data sharing on the test system.
      You have a single-system data sharing group at this point, and this can help you find any initial configuration problems. Make sure that old applications work in this environment.
    3. Install additional members in the test group. Run applications from different members in the group to fully exercise the group buffer pools and cross-system locking.
  2. Move to production.
    When you are ready to move to production complete the following steps:
    1. If your originating member is not already migrated to Db2 12, migrate it from Db2 11 to Db2 12.
      Recommendation: Wait until your system is stable before enabling data sharing . You can enable data sharing on your existing release and then migrate to Db2 12, but it is not recommended, particularly if you plan to migrate soon. Start of changeIf you are in the process of migrating, wait until after the activation of function level 500 or higher before you move to the data sharing mode. End of change
    2. Start of change Verify that function level 500 or higher is activated and that your Db2 system is stabilized. Once the system is stabilized, you can begin using new capabilities. End of change
    3. Tune applications to contain the level of locking and lock contention rates.
      To reduce the effects of locking contention in a data sharing environment, first control locking costs in a non-data sharing environment. This gives you a baseline from which to perform further tuning after the move to data sharing.
    4. Enable data sharing on the originating member, and run applications on this one-member data sharing group.
    5. Install additional members as needed.