IAM/PLEX Implementation
This section provides the outline of the procedure to follow to implement IAM/PLEX. We recommend that you start out with a very limited implementation, and then as you become comfortable with IAM/PLEX, the use of it can be expanded to more data sets. Many of the parameters that control IAM/PLEX can be easily modified while IAM/PLEX is active, which will minimize the need to deactivate IAM/PLEX to broaden the implementation to more data sets. Within any CICS region or batch job, there can be some IAM data sets using IAM/PLEX, while other IAM data sets are not using the IAM/PLEX services.
Careful planning and consideration must be given to how to recover data when a software or hardware error occurs. This is particularly true if you have never used any type of data sharing software in the past. For example, if a batch job abends, you may not be able just to restore a data set and restart the job because of the potential loss of data from CICS users concurrently updating the data set. IAM does provide journaling and recovery capabilities that can be used to perform various types of recoveries. You should determine ahead of time what your needs are, which can be different for your different data sets and applications. Careful planning and testing of recovery procedures will be of great benefit to successfully implementing IAM/PLEX. Refer to IAM/PLEX Data Recovery for more information.
The various tasks necessary to implement IAM/PLEX are shown below. Please be sure to review all of the sections to make sure that nothing is missed as you develop your implementation plan
1 | CHECK | STEP | ACTION |
2 | p | 1 | Set up the IAM/PLEX proc within the appropriate system proclibs, and allocate any required parameter libraries. Refer to IAM/PLEX JCL Procedure for the details on the IAM/PLEX proc and address space requirements. A separate proc will need to be created for each IAM/PLEX address space that is to be executed. Information on allocating the optional record lock recovery data set is in Section 25.06 |
3 | p | 2 | Review and select the appropriate values for the various IAM/PLEX parameters. Review IAM/PLEX Parameters for detailed information on the IAM/PLEX parameters. |
4 | p | 3 | Set up the appropriate criteria for your installation for the IAM/PLEX automatic data set selection. Refer to IAM/PLEX Automatic Dataset Eligibility for the details on automatic data set selection. Set the RLSIAM Global Option accordingly. |
5 | p | 4 | Update your coupling facility policies to define a STRUCTURE, and LOGSTREAM data sets that will use that STRUCTURE in the coupling facility. Each RLSGROUP, if you use more than one, must have its own LOGSTREAM. Up to 10 LOGSTREAMS can be defined using the same STRUCTURE in the coupling facility. Refer to IAM/PLEX Journaling for information on IAM/PLEX journaling. |
6 | p | 5 | Review your COUPLExx member in parmlib and make sure that there are CLASSDEF and PATHIN and PATHOUT statements coded. This sets up defaults for the transport classes used by XCF for signaling purposes. Please refer to MVS Setting Up a Sysplex space for details on setting up the COUPLExx member of parmlib, and to section 5.0 in that space for Planning Signaling Services in a Sysplex. |
7 | p | 6 | Review IAM/PLEX CICS Considerations on CICS Transaction Server considerations. Install and activate the necessary CICS exits provided by IAM in every region that will be using IAM/PLEX. The CICS exits are critical for IAM to perform record locking for CICS. Failure to properly install and implement them will result in record lockouts and other failures. There are no application or JCL changes required for CICS to use IAM/PLEX. |
8 | p | 7 | Review IAM/PLEX Batch Considerations on batch application considerations. For batch jobs that update a large portion of the records in a recoverable file that is processed by IAM/PLEX use of the IAM/PLEX Batch Syncpoint program or AUTOSYNCPOINT is required, along with providing recovery and restart should such programs experience software or hardware failures. |
9 | p | 8 | Plan and develop procedures for data recovery, to be prepared in case of unexpected software or hardware errors occur. Make sure that your implementation for IAM/PLEX journaling will provide the necessary data to perform data recoveries that will be necessary when failures occur. Refer to IAM/PLEX Data Recovery for information on recovery of data for IAMfiles being processed under IAM/PLEX. |
10 | p | 9 | Review IAM/PLEX Operator Commands on the IAM/PLEX operator commands, for information on the various operational requests that can be made of IAM/PLEX. |