Sample report from DFHLSCU

An example of a report produced by DFHLSCU, for estimating the size of a system log, is shown in Figure 7.

Figure 7. Sample report from DFHLSCU
 ************************************************************************
 THE LOGSTREAM CALCULATIONS UTILITY REPORT.
 
   JOURNAL TYPE  : system log.
   INTERVAL      : 000002 minutes.
   AKPFREQ       : 00299
   LOGSNUM       : 0010
   TRANSDUR      : 000003 seconds.
 
 **************** REPORT SUMMARY INFORMATION ****************
   SEGMENT  00000001  1 
 DURATION  00006000 seconds  2 
   TIME  17:12:52.9  3 
 DATE  2002.171  4 
   NUMBER OF BLOCKS       : 00000002   5 
   WRITES PER SECOND      : <1   6 
   AVERAGE RECORD SIZE    : 00000065   7 
   AKP INTERVAL           : 00179400   8 
 
   TYPE  QUANTITY    NUMBER OF BYTES     6.4 EQUIVALENT  9 
   FC    00000000    0000000000000000    0000000000000000
   JC    00000000    0000000000000000    0000000000000000
   TD    00000000    0000000000000000    0000000000000000
   TS    00000000    0000000000000000    0000000000000000
   KP    00000000    0000000000000000    0000000000000000
   RM    00000001    0000000000000066    0000000000000131
   SP   00000009    0000000000000350    0000000000000524
   Other 00000000    0000000000000000      *** NONE ***
   Total 00000010
 
   From this, an AVGBUFSIZE of 00117 was calculated.    10 
 
 **************** REPORT SUMMARY INFORMATION ****************
   SEGMENT  00000002        DURATION  00000075 seconds
   TIME  18:52:52.6         DATE  2002.171
   NUMBER OF BLOCKS       : 00000095
   WRITES PER SECOND      : 00000001
   AVERAGE RECORD SIZE    : 00000206
   AKP INTERVAL           : 00000195
 
   TYPE  QUANTITY    NUMBER OF BYTES     6.4 EQUIVALENT
   FC    00000090    0000000000011700    0000000000020520
   JC    00000000    0000000000000000    0000000000000000
   TD    00000003    0000000000000498    0000000000001461
   TS    00000003    0000000000000150    0000000000000588
   KP    00000000    0000000000000000    0000000000000000
   RM    00000001    0000000000000066    0000000000000131
   SP    00000018    0000000000000702    0000000000001050
   Other 00000030    0000000000003900      *** NONE ***
   Total 00000115
 
   From this, an AVGBUFSIZE of 00302 was calculated.
 
 *******************************************************************************
 The end of the JOURNAL data set has been reached.
 *******************************************************************************
 **************** REPORT SUMMARY CONCLUSIONS ****************   11 
 The following summary contains the highest workload, based
 on the number of blocks written:-
 
   SEGMENT  00000002        DURATION  00000075 seconds
   TIME  18:52:52.6         DATE  2002.171
   NUMBER OF BLOCKS       : 00000095
   WRITES PER SECOND      : 00000001
   AVERAGE RECORD SIZE    : 00000206
   AKP INTERVAL           : 00000195
 
   TYPE  QUANTITY    NUMBER OF BYTES     6.4 EQUIVALENT
   FC    00000090    0000000000011700    0000000000020520
   JC    00000000    0000000000000000    0000000000000000
   TD    00000003    0000000000000498    0000000000001461
   TS    00000003    0000000000000150    0000000000000588
   KP    00000000    0000000000000000    0000000000000000
   RM    00000001    0000000000000066    0000000000000131
   SP    00000018    0000000000000702    0000000000001050
   Other 00000030    0000000000003900      *** NONE ***
   Total 00000115
 
   From this, an AVGBUFSIZE of 00302 was calculated.
 
 ************************************************************
 This section applies to CF logstreams:-                    12 
 
 You are recommended to complete the following definition and use it to
 create a suitable structure for this journal logstream:
 
 
        DATA TYPE(LOGR) REPORT(NO)                          13 
        DEFINE STRUCTURE NAME(LOG_DFHLOG_nnn) LOGSNUM(10)
               MAXBUFSIZE(64000) AVGBUFSIZE(302)
 
 
 In addition, the space required within the Coupling Facility by
 such a journal can be specified using the following definition:
 
        DATA TYPE(CFRM) REPORT(NO)                          14 
        STRUCTURE NAME(LOG_DFHLOG_nnn)
          INITSIZE(2048) SIZE(3328)
          PREFLIST(cf_name) REBUILDPERCENT(1)
 
 
 The following is a typical definition of a logstream using some
 default values, and some calculated from this utility:
 
        DATA TYPE(LOGR) REPORT(NO)                          15 
        DEFINE LOGSTREAM NAME(userid.applid.DFHLOG)
               STRUCTNAME(LOG_DFHLOG_nnn)
               HIGHOFFLOAD(80)
               LOWOFFLOAD(40)
 
 
 If staging is to be used for this logstream, the following value
 is that calculated for the staging data set size. This assumes the worst
 case where only this logstream is actively connected to the structure. If
 more log streams are to be connected in parallel, then this value should
 be replaced by one obtained from dividing it by the number of streams.
 
          STG_SIZE(4155)                                    16 
 
 
 A recommendation for a suitable initial value of LS_SIZE is given below.
 
          LS_SIZE(13)
 
 ************************************************************
 This section applies to DASD-only logstreams:-             17 
 
 You are recommended to complete the following definition and use it to
 create a suitable logstream:
 
        DATA TYPE(LOGR) REPORT(NO)                          18 
        DEFINE LOGSTREAM NAME(userid.applid.DFHLOG)
               DASDONLY(YES)
               HIGHOFFLOAD(80)
               LOWOFFLOAD(40)
               STG_SIZE(1010)
               MAXBUFSIZE(64000)
               LS_SIZE(252)
 
************************************************************
 General information section:-
 
 1)  The LS_SIZE parameter specifies (in 4K blocks) the size of the logstream
 offload data sets (secondary storage) allocation. If the size parameter is
 omitted, and the size is not specified in the SMS (System Managed Storage)
 constructs, the size is taken from the ALLOCxx member of SYS1.PARMLIB. The
 default value is 2 tracks. Using this default size can lead to an excessive
 number of data set allocations. The value specified depends upon the logstream
 and the amount of data which is offloaded. For a DFHLOG or DFHSHUNT logstream,
 sized so that no data is normally offloaded during offload processing, the
 value of LS_SIZE should be between 20% to 25% of the logstream primary storage
 capacity.
   For user journals and forward recovery logs, LS_SIZE should be large enough
 to contain the volume of data written during the critical CICS processing
 period of the day, in order to eliminate offload data set allocation delays.
 

Notes:

 1  This indicates the segment of the journal data set on which the utility is operating. Each segment holds journal records made over the period specified in the INTERVAL SYSIN statement, unless it is the final segment (when it contains journal records made between the end of the previous segment and the end of the journal data set).

 2  This indicates the time duration covered in the segment. It corresponds to the value on the INTERVAL parameter unless it is the final segment (when it is the time between the end of the previous segment and the end of the data set).

 3  This is the time at which the data being analyzed in the segment commenced its generation.

 4  This is the date on which the data being analyzed by DFHLSCU was generated. It is of the form yyyy.ddd where yyyy is the year, and ddd is the day within the year.

 5  The number of journal blocks contained in the segment is shown here.

 6  The average number of journal writes per second is shown here. Where the value is greater than 1, its value is shown as an integer value. Where the value is between 0 and 1, '< 1' is shown, and the estimates calculated by DFHLSCU (if based on this segment of the data set) will be inaccurate. Where it is 0, '0' is shown.

DFHLSCU’s estimates are most accurate when the value for writes per second is high. (The maximum value is 25.)

 7  The average size of the records in the interval is shown here.

 8  The average time interval between activity keypoints is estimated from the information in the segment. This will only appear in the output if the JNLTYPE is SYSTEM.

 9  A section containing information about the specific records type found in the segment is provided. Record types included in this section are those generated by:

The 'QUANTITY' column shows the number of records of each type that was found. The total of the values in this column is given. The 'NUMBER OF BYTES' column shows the number of bytes that these records represent. The '6.4 EQUIVALENT' column shows the number of bytes, as calculated by DFHLSCU, that would be required at CICS Transaction Server for z/OS, Version 3 Release 1 for an equivalent record.

 10  For each section, a value of AVGBUFSIZE is calculated.

 11  Start of the report’s conclusion. The conclusion informs you which segment contained the most journaling activity and is based on the segment with the highest calculated value for AVGBUFSIZE.

 12  Start of the report’s recommendations for log streams that use coupling facility structures.

 13  For a CF log stream, the recommended log stream structure definition to be included in your DEFINE STRUCTURE jobs.

 14  For a CF log stream, the recommended coupling facility space definition to be edited by you for inclusion in the CFRM policy.

 15  For a CF log stream, the recommended log stream definition. Note that the definition assumes that duplexing of data is not required. If duplexing is required, add to the definition:

STG_DUPLEX(YES) DUPLEXMODE(COND)

 16  For a CF log stream that uses duplexing, the recommended value for the STG_SIZE attribute on your DEFINE LOGSTREAM job. This is the size of the staging data set required by the log stream. It does not take into account any other log streams that might be connected, at the same time, to the log stream structure. If other log streams are to be connected, you should calculate a value for STG_SIZE based on the value recommended by DFHLSCU, divided by the number of estimated connections.

 17  Start of the report’s recommendations for DASD-only log streams.

 18  For a DASD-only log stream, the recommended log stream definition.

Additional Note

The AKPFREQ and TRANSDUR information will only appear in the report if the JNLTYPE is SYSTEM. The total value in each summary section is that of the records which are relevant to the calculations that the utility carries out. It does not include records that can never occur in a CICS Transaction Server for z/OS, Version 3 Release 1 journal.

Related reference
Log stream sizing migration utility (DFHLSCU)
Recommendations made by DFHLSCU
Job control statements to run the DFHLSCU program
SYSIN control statements for the DFHLSCU utility
Considerations when using DFHLSCU
DFHLSCU return codes
[[ Contents Previous Page | Next Page Index ]]