Preparing to collect IMS data

To collect IBM IMS log records, review your IMS environment and choose the appropriate method.

Before you begin

The Z Common Data Provider provides two different approaches to collect IMS log records:

  • Collecting IMS records by using IMS user exit
    • This approach has the least latency for collecting IMS log records. It requires the Z Common Data Provider provided IMS user exit to be installed in the IMS control region. The IMS user exit collects the selected IMS log records and writes to System Management Facilities (SMF). Subsequently, the SMF records can be collected and processed by the System Data Engine or the Data Collector.
  • Collecting IMS records from IMS online log datasets (OLDS)
    • This approach has a higher latency than the previous approach, but it avoids the additional overhead on the IMS systems. The approach is recommended for busy IMS systems. A separate System Data Engine is necessary to collect IMS log records directly from IMS OLDS.
The following table highlights the differences between the two approaches.
Table 1. Differences between the two approaches for collecting IMS records
  Collecting IMS records by using IMS user exit Collecting IMS records from OLDS
Data latency Low.

SMF records are written after a block of data is successfully written to OLDS.

 High.

IMS log records can be collected only when an active OLDS data set has switched to a new data set.

IMS user exit requirement The Z Common Data Provider provides IMS user exit that is needed to be installed in the IMS control region. No IMS user exit is required.
Overhead on IMS systems The IMS user exit running in the IMS control region adds additional overhead for writing SMF records. No additional overhead in the IMS control region.
System Data Engine instance requirement A single System Data Engine instance can be used to collect IMS records that are written by IMS user exit and other SMF records. A separate System Data Engine is required to collect IMS log records from OLDS. A System Data Engine can collect either SMF records or IMS log records from OLDS, but not both.
Data Collector instance requirement A single or separate Data Collector instance can be used to collect IMS records that are written by IMS user exit and other SMF records. N/A