WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

14.9 System programmer considerations
This section contains some additional hints and tips for system programmers that
should be taken into consideration when installing and configuring a WebSphere
Application Server for z/OS V7.0 environment.
14.9.1 Systems Management Facility enhancements
WebSphere Application Server for z/OS is capable of writing z/OS Systems
Management Facility (SMF) records for performance tuning and charge-back.
Prior to WebSphere Application Server for z/OS V7.0
Since Version 4 of WebSphere Application Server, SMF record 120 was used to
log usage data.
SMF reserves record type 120 for WebSphere activity data. Record 120 includes
a number of subtypes, each of which contains a subset of the data. This
fragmented view of the data is due to internal divisions in the product. Some
record 120 subtypes are created by the WebSphere Application Server runtime
(subtypes 1 and 3), while others are created by the Web containers and EJB
containers (subtypes 5, 6, 7, and 8). Because each subtype provides only a
partial view of the activity, you need to correlate several subtypes to get a more
complete picture of what the server is doing. This will however increase the
overhead of SMF usage.
New in WebSphere Application Server for z/OS V7.0
In V7.0 a new subtype 9 record, called Request Activity Record, has been added.
It can be used to create/write resource usage records without unreasonable
overhead. Any data collection that adds substantially to the cost of acquiring that
data is optional. You can activate or deactivate this record dynamically.
About the new subrecord: Because the new SMF 120-9 subrecord
consumes less processing time than the collection of multiple subrecords, we
suggest the usage of the new subrecord. The old subrecords remain valid and
can be used with WebSphere Application Server for z/OS V7.0.
The subtype 9 gives you the option to monitor which requests are associated
with which applications, how many requests occur, and how much resource each
request uses. You can also use this record to identify the application involved and
the CPU time that the request consumes. Because a new record is created for
each request, it is possible to determine the number of requests that arrive at the
system over a specific period of time.
466 WebSphere Application Server V7.0: Concepts, Planning, and Design