Configuring an IMSplex with CSL

An IMS control region that is running without CSL must be stopped and restarted to connect to CSL. When CSL is introduced into the IMSplex, the IMS control regions can be stopped and restarted one at a time. The entire IMSplex does not need to be shutdown to introduce CSL.

To configure an IMSplex with CSL, you must initialize at least one of each of the following IMSplex components:

  • DB/DC, DCCTL, or DBCTL IMS control region
  • DBRC for each IMS control region
  • Operations Manager (OM)
  • Structured Call Interface (SCI) on each operating system on which an IMSplex member is running
  • CQS when message queues are shared or RM is used with the resource structure to manage global resources

It is also strongly recommended that you also initialize a Resource Manager (RM) and a resource structure. Although an RM and a resource structure are not required, you cannot share or manage resources globally.

Optionally, you can have the following in your IMSplex:
  • CSL Open Database Manager, which provides distributed and local access to IMS databases that are managed by IMS DB systems configured for either the DBCTL or the DB/TM environments in an IMSplex.
  • Data sharing of one or more databases in a DB/DC or DBCTL environment.
  • One DL/I address space and 1 to 999 dependent regions for each IMS control region.
  • Shared queues.
    Important: All IMS control regions should share message queues. Otherwise, shared queues should not be used. Running in a mixed environment where some of the queues are shared and others are not can result in an unpredictable or misleading output from type-2 commands, which are entered through the OM API.
  • Any number of batch (DLIBATCH or DBBBATCH) regions. OM and RM do not interact with batch regions; therefore, they do not affect management of batch regions.
  • IMSRSC repository for the shared resource definitions, along with the Repository Server (RS) address space.

To include CSL, an IMS control region must be started with the CSLG= parameter, or if the DFSDFxxx member of the IMS PROCLIB data set includes the COMMON_SERVICE_LAYER section , the DFSDF= parameter. The minimum configuration for the CSL is to have only one SCI on each operating system where an IMSplex component resides (including IMSplex components like TSO SPOC and CQS), one or more OMs anywhere in the IMSplex, and one or more RMs anywhere in the IMSplex.

How many RMs and OMs to have depends on your requirements. An outline of CSL configuration rules follows:

  • Only one SCI can run on an operating system for a given IMSplex. Multiple IMS systems on the same operating system use the same instance of SCI to communicate within the same IMSplex. If one or more IMS systems on the same operating system are associated with multiple IMSplex systems, you must run a separate instance of SCI for each IMSplex.
  • At least one OM must be active in an IMSplex. You can have one or more OMs active on one or more operating systems.
  • An RM is not required, but at least one active RM is recommended in an IMSplex. You can have one RM active on any number of operating systems. If you have more than one RM, you must also have a resource structure.
  • A CSL configuration with an RM is required if IMS is enabled to use the repository.