There are two types of log streams, and SMF logging supports both
of them:
- Coupling facility log streams, where data is stored in a coupling facility structure and then offloaded to DASD. A coupling facility log stream is ideal for merging SMF data from multiple systems. Note that a systems' SMF id, or "SID", should be unique within the sysplex.
DASD-only log streams, where data is stored in local
storage buffers and then offloaded to DASD. Note the following about
DASD-only log streams:- DASD-only log streams can only be single-system in scope and only one system can write data to any given DASD-only log stream.
- DASD-only log streams may experience delays in connecting at IPL because system logger's recovery processing involves offloading data from its interim storage to the offload data sets. These delays do not affect coupling facility log streams.
