IAMSMFVS Reports

Another reporting alternative, if the IAM SMF records are being recorded, is to use the IAMSMFVS program. IAMSMFVS provides a handy way to monitor and track the use of IAM within an installation, or by particular applications. This program produces three reports, an EXCP report, a Data set Report, and a Size Report. Each report summarizes activity with one line per data set and reports on different statistics and attributes. The EXCP report and the Size report, by default reports the top 100 data sets, while the Data set Report contains all of the data sets that were processed. Some customers have used the IAMSMFVS report to watch and determine when various IAM data sets may need to be reorganized based on a percentage of the overflow area in use.

Example IAMSMFVS JCL

An example of the JCL and control card to run IAMSMFVS is shown below. Full details on running IAMSMFVS and on the control card input are provided in the System Analysis Utilities IAMSMFVS — Data Set Analysis Program of the space. IAMSMFVS requires SMF type 30, subtype 4 records or SMF type 4 records to produce reports. There is one keyword specified on the example REPORT control card, which is DSORG=IAM. By default, IAMSMFVS will produce reports on IAM and VSAM.

Example of JCL to run IAMSMFVS (EX1073A)

A few additional keywords for the REPORT control card that you might find useful for IAM reporting include:

CURRENT - Specifies that the current overflow usage values be reported on, rather than the maximum amount encountered in the data.

DETAIL - The EXCP report will contain a breakdown for each use of the file, including job, step, and program name information.

DSG - Specifies only data sets that begin with the values specified will be included in the reports. For example, DSG=PROD, or DSG=(PROD1,PROD2.AP,PROD3.AR)

MAXDSNS - Specifies the maximum number of data sets that IAMSMFVS will accumulate statistics for. The default value is 60000. Note that for VSAM, each component counts as a data set, plus the cluster name. So, a KSDS will require 3 entries, and an ESDS will require 2 entries. IAM data sets only require 1 entry each.

MAXREPORTS - Specifies the number of data sets that will be included in the EXCP and the SIZE reports. Default is 100.

Sample IAMSMFVS Summary Report

The first page of the IAMSMFVS output consists of a summarization of all of the data that was selected for reporting, including totals for data set names, job names, total EXCP counts by access method, and DASD space used by access method (that is., IAM and VSAM). Below is a sample output of the first page.

Sample IAMSMFVS Summary Report

Sample IAMSMFVS IAM EXCP Report

After the Summary Report, IAMSMFVS produces the EXCP report. There is a separate EXCP report for IAM data sets and VSAM data sets, if both types of data sets are being reported on. In our sample case, only IAM data sets are being reported, so there is only an IAM EXCP report. Below is a sample of an IAM EXCP report, as produced by IAMSMFVS. Entries are sorted by largest to smallest EXCP count. As stated previously, only the top 100 data sets are included, unless MAXREPORTS has been specified with a different value.

Sample IAMSMFVS IAM EXCP Report

The Use Count is the number of SMF records processed for the data set. The following fields represent the accumulation of data from all of the records: EXCPS, READS, INSERTS, UPDATES, and DELETES. If the keyword CURRENT is included on the REPORT request, then the Overflow statistics are from the most recent record, otherwise they are the maximum encountered. The RECORDS and TRACKS USED are the maximum encountered.

Sample IAMSMFVS Data set Report

The next report is the Data set Summary Report. This report is sorted by data set name, and includes all of the data sets selected for this execution of IAMSMFVS. The information presented includes basic data set attribute information, such as record length, key length, relative key position, and the block size or CI size.

Sample IAMSMFVS Data set Report

The RECFM values for IAM data sets have the following meanings:

VE: Enhanced format, variable length records

VO: Enhanced format, variable overflow

DC: Data Compressed

Sample IAMSMFVS IAM Size Report

The Size report is broken out in a manner similar to the EXCP report. There are separate reports for IAM and VSAM data sets, and the reports consist of the largest 100 data sets, or whatever value was specified on the MAXREPORTS operand. This report contains the most information about the overflow area use, so it would be the one to use for a determination as to whether reorganization is needed.

Sample IAMSMFVS IAM Size Report

For Enhanced Format files, the Maximum Overflow Records are based on either the user specified number of overflow records, from the CREATE O= override. The O= override value is retained for informational purposes to aid in making decisions about when the data set should be reorganized. IAM makes no guarantee that there is sufficient DASD space for IAM to actually keep that number of records in the overflow area. Also, the overflow may be able to hold more records than the number specified, so the overflow used percentage can exceed 100.

If no override had been provided, then maximum overflow records is calculated based on the number of extended blocks currently allocated to the data set.