Setting up and managing SMF

Setting up SMF requires your installation to decide what kind of records it wants SMF to produce or what information it wants SMF to gather. Then you can make decisions about how to set SMF up to meet these requirements. You'll also want to consider the following points in planning your SMF configuration:
  1. What records must SMF produce to give you the information your installation wants?
  2. What is the environment SMF will run in and how many jobs run through the system? (The number of records generated by SMF depends on the number of jobs.)
  3. Are you running program products (such as RMF or DB2®) that might require special considerations for SMF? (See Special considerations for DB2, JES3, and RMF.)
  4. What is the impact of the system configuration, particularly the type and degree of multiprogramming?
  5. How much contention is there for the resources that SMF needs?
Once you've considered some of the basics about what you want SMF to do in your installation, your next decision is whether you want to write your SMF records to log streams or to SMF data sets.
  • When you use SMF data set recording, SMF writes records to the SMF data sets you allocate. The size of the data that the system can write to SMF data sets is constrained by the VSAM control interval size—SMF can only write one control interval at a time. See Setting Up and Managing SMF Recording to Data Sets.
  • When you use SMF logging, SMF writes records to the system logger managed log streams that you set up. SMF can write much larger chunks of data to the log stream than it can to SMF data sets. This has the potential to make writing SMF records faster, which could mean collecting more data.

    SMF logging also allows you to group different SMF record types into different log streams defined for different purposes. For example, you might want a log stream for job-related SMF data and one for performance SMF data. SMF can also write a single record to multiple log streams. Record 30, the common address space work record, for example, might well fit into both the job-related log stream and the performance log stream.

    You can set up either of the following types of log streams:
    • Coupling facility log streams, where data is stored in a coupling facility structure and then offloaded to DASD.
    • DASD-only log streams, where data is stored in local storage buffers and then offloaded to DASD.
    See Setting up and managing SMF recording to logstreams
Now that you've made some basic decisions, use the following topics to set up SMF to meet your installation's requirements: