Analysis of fields

SMF fields relating to resource events, either structure full or staging data set full conditions, should be handled depending on the following:

Whether the resource is shared sysplex-wide and each system will take action.
Whether the resource is shared sysplex-wide but only one system will take action.
Whether the resource is consumed on a system-local basis.

To obtain a sysplex-wide view of system logger activity, correct processing for most SMF 88 data fields is to sum the field contents for the target interval across all the SMF 88 records produced in the sysplex. There are, however, exceptions to this rule. Because each system must take its own action — that is, wait for an ENF signal indicating that system logger is available — an analysis program should use the maximum value for these fields: SMF88ERI, SMF88ERC, and SMF88ESF. For example, if a structure rebuild is initiated in a sysplex with three systems, the event is recorded on all three systems. The correct number of structure rebuild initiations is not three, however, it is one, or the maximum number provided SMF88ERI.

For dasd only log streams, staging data sets are a required part of the log stream configuration. For coupling facility log streams, on the other hand, use of staging data sets implies a trade-off between performance workload and data integrity. You should try to tune the staging data set size to minimize the number of Staging_Dataset_Threshold_Hit conditions. Without this type of tuning, such conditions can impact performance during staging data set processing. Note that only an installation can determine what the proper trade-off between performance and data integrity should be. For more information about staging data sets, for coupling facility log streams, see z/OS MVS Setting Up a Sysplex.

Because system logger maintains interim storage differently for coupling facility based versus dasd only log streams, the difference is reflected in SMF record 88 report:

For a coupling facility based log stream, Structure (Interim Storage) Section of the record 88 report shows information about usage of coupling facility structure space allocated for a log stream and the flow of log data through the structure.
For a dasd only log stream, the Structure (Interim Storage) section of the record 88 report shows information about usage of staging data set space and flow of data through the staging data set for the log stream.
Not all fields in the Structure (Interim Storage) Section of the record 88 report apply to dasd only log streams. For a dasd only log stream, fields that do not apply will contain zeros. Field SMF88STN contains *DASDONLY* for a dasd only log stream because there is no structure name. Use this field to identify a dasd only log stream.