Special Usage Considerations › Interpreting SNAPDUMP Output

Interpreting SNAPDUMP Output

The CA JARS Report Writer performs extensive validity checking on the SMF input file. Blocks of SMF data are read and deblocked by the Report Writer, rather than the operating system, in order to give the program greater control over the action to be taken when errors are encountered. SMF records are checked for invalid data as they are read. The following are the reasons for this validity checking:

1. To allow processing to continue, if possible, in spite of the presence of invalid data in the input data set.
2. To prevent the inclusion of erroneous data in the output Job Accounting reports and history files.

When invalid data is encountered, it is discarded. Message CAJS941I at the end of the input phase of a run indicates that invalid data has been detected. This message gives the number of segments and the number of blocks discarded because of I/O errors or errors attempting to deblock record segments with invalid control information in the segment description words. Message CAJS944I gives the number of additional records that have been discarded for failure to conform to correct SMF record formats.

When data is discarded, it is also displayed on the SNAPDUMP output file by means of the OS SNAP macro. A maximum of ten SNAPs are issued by the Report Writer in any given run. (Thereafter, discarded data is not SNAP'd, but the discarded blocks, segments, and records continue to be counted.)

The first item in each SNAP is one of the following Report Writer control blocks: the GETCB, which contains information describing the status of input and deblocking operations against the SMF input file; or the RCAREA, which contains information describing the current status of SMF record processing. The contents of these two control blocks is described below.

Following the GETCB or RCAREA, the data in error is displayed. (The exact data displayed depends on the reason for the SNAP, as described below.)

At the end of each SNAP, a message appears containing a one-letter reason code which is used to determine the cause of the SNAP. The following paragraphs explain possible reason codes.