Capturing JVM usage statistics

You can enable IMS to capture the usage statistics of persistent Java virtual machines (JVMs) that run in an IMS dependent region. The JVM usage statistics are captured as type-29, subtype-2 records in z/OS System Management Facility (SMF).

Before you enable IMS to capture JVM usage statistics, ensure that all of the following prerequisites are met:
  • The latest version of the IMS Universal JDBC driver is downloaded and all of your existing IMS Universal JDBC driver files are replaced with the files of the latest version. In particular, you must use the latest version of the imsudb.jar and imsutm.jar files.
  • SMF is installed in z/OS®.
  • SMF is configured to accept type-29, subtype-2 records in the settings for SMF parameter SYS1.PARMLIB(SMFPRMxx) in z/OS.

  • Define the BPX.SMF or the BPX.SMF.type.subtype FACILITY class profile according to your needs. Defining the BPX.SMF.29.2 FACILITY class profile requires a clean program-controlled environment. For more information about defining BPX.SMF or BPX.SMF.type.subtype, see z/OS UNIX System Services Planning on setting up the UNIX-related FACILITY and SURROGAT class profiles .

    For example, once you have activated the FACILITY class with the SETROPTS CLASSACT FACILITY command, you can use the commands below to permit access to either BPX.SMF or BPX.SMF.29.2. Please see the documentation for each of those commands for more details:
    • RDEFINE FACILITY BPX.SMF UACC (access-authority)
    • PERMIT BPX.SMF CLASS (FACILITY) ACCESS (access-authority) ID (name)

    • SETROPTS RACLIST (FACILITY) REFRESH

    Or
    • RDEFINE FACILITY BPX.SMF.29.2 UACC (access-authority)
    • PERMIT BPX.SMF.29.2 CLASS (FACILITY) ACCESS (access-authority) ID (name)
    • SETROPTS RACLIST (FACILITY) REFRESH

IMS queries z/OS to confirm that SMF type-29, subtype-2 records are to be captured. If not, IMS does not call SMF to write the record.

Procedure

To enable IMS to capture JVM statistics, specify the following parameters in the DFSJVMEV member of the IMS PROCLIB data set or, if you use the //STDENV DD statement to configure JVM environments, in the shell script that is referenced by the DD statement.
JLEOPT=N
Specifies that a persistent JVM is used for the IMS dependent region.
SMFINTERVAL
Specifies the time interval in milliseconds that is used to log JVM statistics. 6000 is the recommended value.