4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 06018: MFS Directory I/O Rate Exceeds Standard

06018: MFS Directory I/O Rate Exceeds Standard

    FILE:            IMS System Activity
    SAS FILE NAME:   DETAIL.IMSISY01
    SOURCE LOCATION: sharedprefix.MICS.SOURCE(DYIMSEXC)

    SEVERITY:        Critical      (SEVERITY='C')
    MANAGEMENT AREA: Performance   (MGMTAREA='PERFORMANCE')

    PURPOSE:  Identifies the time period during which the
message MFS pool was over-committed.

    RATIONALE:  An abnormally high MFS Directory I/O rate may
indicate misuse of MFS.  Proliferation of formats with no
attempt to use common displays may lead to high I/O here.
The use of the in-core directory $$IMSDIR is strongly
recommended.  As each entry is only fourteen bytes, most
installations include all formats in this directory.  If this
is the case, there should be no directory I/O.  However, if
there are more formats than will fit in $$IMSDIR (2339
entries in a 32K pool out of the MFS pool), the most often
referenced formats should be included to minimize I/O.  A
large I/O rate indicates a non-optimum choice of formats to
be included in the directory.

    DEFINITION:  This exception is detected when the MFS
directory I/O rate exceeds the installation-defined limit.

    EXCEPTION STATEMENTS:  The SAS statements identifying the
exception situation and describing the condition are stored
in the source member named in SOURCE LOCATION and are
described below:

*
**  06018
**  MFS DIRECTORY I/O RATE EXCEEDS STANDARD
*;
IF (ISYFMDIO/DURATION) > directory-I/O-rate
 THEN DO;
  X = ISYFMDIO / DURATION;
  EXCCODE='06018'; SEVERITY='C'; MGMTAREA='PERFORMANCE';
  EXCDESC1=
  'MFS DIRECTORY I/O RATE EXCEEDS STANDARD';
  EXCDESC2='MFS DIRECTORY I/O RATE ='
           || PUT(X,7.2);
  LINK HIT;
END;

    THRESHOLD MODIFICATION:  Modify the value used for the
MFS directory-I/O-rate.