Instrumentation Server

The Instrumentation Server presents a global view of the Trace Browse facility by running many servers in a single logical partition (LPAR) or across a sysplex, and routing Trace Browse information to one repository. This is accomplished using Cross System Coupling Facility (XCF) services.

When multiple servers run in a single LPAR, XCF converts the call to a z/OS cross memory call so that XCF is not used.

The SIS ERRORONLY server limits the trace data being sent to the Instrumentation Server to contain only 'significant' information. This means that the IS Trace Browse wraps less frequently and is more useful. You use the SIS ERRORONLY server when you only want to trace error messages or if you are running in a high-volume environment.

The Instrumentation Server is not recommended for a high-volume environment where large amounts of tracing is occurring. The Instrumentation Server address space increases CPU usage by your IBM Data Virtualization Manager for z/OS environment based on the number of messages being processed. CPU increases could range around .0003 seconds of CPU per Trace Browse message. However, this number is relative to the type and speed of the processor where the IBM Data Virtualization Manager for z/OS subsystems are installed and should not be used as a definitive calculation. The Instrumentation Server may also affect transaction response time relative to the number of messages that are generated per transaction and the extra CPU costs for those messages.

Instrumentation Server benefits

There are many benefits to using the Instrumentation Server:

  • The Instrumentation Server decreases the virtual storage requirements for the main Data Virtualization Manager server address spaces servicing transaction requests by removing the storage requirements for Trace Browse.

  • The Instrumentation Server provides a global view of tracing activity for all your Data Virtualization Manager server instances in a single z/OS LPAR or across a sysplex into a single Instrumentation Server.

  • The Instrumentation Server provides a larger trace data set to be used than the main Data Virtualization Manager server address space. This also allows for more trace data to remain in the Trace Browse display.

  • You may also want to have one IS per IBM Data Virtualization Manager for z/OS subsystem to take advantage of the preceding first and third bullets.