SMF 120.9

IBM WebSphere Application Server for z/OS SMF 120 Subtype 9
Company type	Software feature
Industry	Information technology, Software
Headquarters	United States
Products	SMF 120.9 record for request activity monitoring
Website	www.ibm.com/support/knowledgecenter

The SMF 120 Subtype 9 represents a recently introduced SMF record, launched alongside IBM's WebSphere Application Server for z/OS Version 7. Developed in response to user input, it overcomes the constraints found in earlier WAS z/OS SMF records (Subtypes 1, 3, 5, 6, 7, and 8), which continue to be accessible but have largely been replaced by Subtype 9.

Known as SMF 120.9, this record addresses two primary challenges:

The complexity of analyzing requests due to data being dispersed across several subtypes
High resource consumption associated with previous SMF records

Employing a per request architecture, SMF 120.9 consolidates all pertinent information into a single record per request, removing the necessity for linking multiple records. Enabling this feature results in roughly a 1.5% increase in system CPU overhead when performing fundamental activity monitoring.

SMF 120.9 Sections

The SMF 120.9 format consists of ten distinct sections that provide comprehensive details about each request. Certain sections are optional and can be configured based on administrative preferences:

Server details independent of platform
Server specifics for z/OS
Request information platform-neutral
Request information specific to z/OS
Optionally included z/OS formatted timestamps
Network-related data covering HTTP, SIP, and IIOP protocols
Classification metadata
Optional security-related information
Optional CPU utilization breakdown
Optional user-defined data—through the com.ibm.websphere.smf API, administrators can append up to five user data segments, each with a maximum size of 2K bytes

Comprehensive field definitions and explanations are provided in IBM's Information Center and the WP101342 technical document authored by the feature’s original architect.

MODIFY Support

On z/OS systems, operators can dynamically alter started tasks using modify commands, allowing changes to runtime behavior within predefined environmental constraints.

For WAS on z/OS, the modify command applies to the controller JOBNAME with support for these parameters:

SMF,REQUEST,ON | OFF
SMF,REQUEST,CPU,ON | OFF
SMF,REQUEST,SECURITY,ON | OFF
SMF,REQUEST,TIMESTAMPS,ON | OFF

Sample Java SMF 120.9 Record Browser

A sample Java application is available for inspecting dumped SMF 120.9 records, providing both detailed and summary perspectives of their contents. This tool can be accessed by registering at this link.

This browser is intended primarily for format validation, record examination, and limited-scale analysis rather than as a substitute for comprehensive SMF record analysis software.

External links