6. DATA SOURCES › 6.1 Data Collector Options and Operation › 6.1.2 VM Monitor Data Options

6.1.2 VM Monitor Data Options

VM monitor files are written into virtual storage by CP and
retrieved by an application program that resides in a virtual
machine.  The virtual storage is defined by a shared segment
that is accessed by CP and the application, simultaneously.
The application provided by IBM is the CMS program MONWRITE.
The MONWRITE program will access the shared segment and write
the data either to disk or tape.  MONWRITE output is in a
special format that contains control information that is a
direct image of the data in the DCSS.  The MONWRITE output
file must be processed by the VM Data Transfer Program to
extract the data from the control information and create
standard variable length records for processing by
the CA MICS Analyzer Option for VM/CMS.

Use the CP MONITOR command to set the options for Monitor
data collection.

Suggested parameters:

1.  Enable sample domains STORAGE, PROCESSOR, USER, and I/O.
    Domains SYSTEM and MONITOR are automatically enabled.  In
    the I/O Domain, enable only CPVOL devices for data
    collection unless some other volumes also require
    tracking.  This will minimize data volume.  It is not
    recommended that sample data collection restrictions be
    implemented for the USER domain as this will affect
    active users and storage utilization measurements in the
    VMXSGP file.

2.  Enable event domains STORAGE, I/O, and PROCESSOR.  This
    provides configuration change data at very low overhead.
    The amount of data is minimal.  If you want to track
    interactions (IUCV and VMCF activity) for specific users,
    enable the USER domain for these users only.  Due to the
    potential data volume, it is not recommended that event
    collection be enabled for all users.

    Enable the SCHEDULER domain to collect system timer pop
    data and scheduler parameter change data.  To do this,
    define or determine a userid that is never logged on or
    that is logged on infrequently, and enable SCHEDULER data
    collection for that user.  The userid of a virtual
    machine is mandatory for SCHEDULER domain collection.

3.  If data is produced that your site does not need to
    process, the data can be dropped in the VM Data Transfer
    Program, in _USRSEL in the DAILY update, or in the
    _USRSfff macro in the DAILY update.  Care should be taken
    when selecting which monitor records to dropped.  Certain
    Domain 1 configuration records should not be dropped.
    See Section 6.2.5 for a list of configuration records
    required by the CA MICS Analyzer Option for VM/CMS.  For
    information on coding these macros, see chapter 10.

4.  Set the monitoring interval to one minute and the high
    frequency sampling interval to one second.  If the data
    volume is so high that problems occur in the DAILY update
    due to DASD limitations, the monitoring interval can be
    lengthened.

    Note:  Lengthening the monitoring interval is not
    recommended because data distortion occurs. Data will be
    missing from domain 4 (USER) data and consequently from
    the VMX User Activity Sample Data File (VMXVXU). A number
    of elements in the VMX System Global Data File (VMXSGP)
    are also derived from domain 4 data.  These elements, and
    any computed elements based on them, will be affected by
    lengthening the interval.  If the monitoring interval is
    lengthened, it is not necessary to change the high
    frequency sampling interval.  The high frequency sampling
    interval does not affect data volume.

    Examples:

    CP MON EVENT  EN I/O ALL
    CP MON EVENT  EN PROCESSOR
    CP MON EVENT  EN STORAGE
    CP MON EVENT  EN SCHEDULER USERID $ALLOC$
    CP MON SAMPLE EN I/O CPVOL
    CP MON SAMPLE EN I/O VOL CMS001 CMS002
    CP MON SAMPLE EN USER ALL
    CP MON SAMPLE EN PROCESSOR
    CP MON SAMPLE EN STORAGE
    CP MON INTERVAL 1 MINUTE
    CP MON RATE     1 SECOND
    MONWRITE MONDCSS *MONITOR DISK <file id>
    #CP MON START

    Notes:

    The MONWRITE command MUST be started before the MONITOR
    START command can be issued. The name of the file created
    by MONWRITE can be chosen for your site.

    Each monitor file processed by the VM and CMS Analyzer
    MUST begin with configuration data.  The configuration
    area time limit must be examined to ensure that MONWRITE
    is able to process configuration records within the time
    limit. In order to cut a monitor file, MONWRITE must be
    stopped by a CP EXTERNAL command or MONWSTOP immediate
    command. However, monitoring is stopped only by the
    MONITOR STOP command.

    The MONITOR domain (1) and the SYSTEM domain (0) cannot
    be disabled from sample data collection.  Domain 1
    contains the configuration data that is required by the
    CA MICS Analyzer Option for VM/CMS.

    Examples:

    Monitoring is stopped when MONWRITE terminates:

    #CP EXTERNAL     (or MONWSTOP)
                -->  terminate MONWRITE and monitor
    MONWRITE MONDCSS *MONITOR DISK <new file id>
                -->  start MONWRITE again
    #CP MON START
                -->  start monitor


    In shared mode, monitoring does not stop unless a
    MONITOR STOP command is issued.  Thus, there is no need
    to issue another MONITOR START command for continuing
    monitoring:

    #CP EXTERNAL     (or MONWSTOP)
                -->  terminate MONWRITE
    MONWRITE MONDCSS *MONITOR DISK <new file id>
                -->  start MONWRITE again

5. The CONFIG size (CP MONITOR SAMPLE CONFIG SIZE and (CP
   MONITOR EVENT CONFIG SIZE) must be large enough to store
   configuration information for all hardware, devices, and
   virtual machines connected to the VM system.  If CONFIG
   SIZE is not large enough, configuration records could be
   dropped during monitor data collection. We recommend that
   the CONFIG size be 30% larger than the space required to
   hold all configuration records.

   See the IBM z/VM documentation for more information on
   CONFIG SIZE.