Strobe and DB2/CICS performance issues
agburke 060001QPDN Visits (2029)
A DB2 9 for z/OS customer in NFM ran into an issue where DB2 began to run short on 31-bit virtual storage and DSNVMON messages appeared in the log:
DSNV508I -DB2 DSNVMON - DB2 DBM1 BELOW-THE-BAR 351
At the same time the CICS regions processing slowed down significantly, and these threads remained in DB2 longer than normal.
The situation manifested itself in the following way.
While Strobing DB2 (v9 NFM) with CICS Strobe 'hung',
and failed with:
STR3111E STRBFIFA.PrIf2000 Fif* Attach failed
STR3247E STRBFIFR: -STA TRA(PERF) command failed(timeout), shutdown in
progress. The Strobe log contains abend U0522 at 95DBF4BE
Strobe support Recommendations:
1) Set Strobe Parm to DB2IFIFLAG=0010 to enable Auto filtering of DB2
2) Apply PTF V60621A from Strobe maintenance file (42007). This PTF
addresses abend U0522 ABEND @ STRBGBES - STA TRACE(P) T
This PTF has also resolved similar CICS errors at some of our other accounts as well.
Both cases that were repported to us were resolved by it. They reported
that all their CICS' regions 'went down' during a Strobe measurement
because DB2 was not responding but recovered after Strobe ended. The
U0522 abend occurred as well. One of the cases also reported CICS
storage shortages during the measurement. PTF V60621A was the
resolution in each case.
After applying PTF V60621A and updating the DB2IFIFLAG to 0010 Strobe
must be recycled.