4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 02105: Log Chan / LCU Delayed I/O (All Reasons) Exceeds Max

02105: Log Chan / LCU Delayed I/O (All Reasons) Exceeds Max

    FILE: Logical Channel Activity File
    SAS FILE NAME: DAYS.SCPLCA01
    SOURCE LOCATION: prefix.MICS.USER.SOURCE(DYRMFEXC)

    SEVERITY: Impacting            (SEVERITY='I')
    MANAGEMENT AREA: Performance   (MGMTAREA='PERFORMANCE')

    PURPOSE:  Identify excessive I/O queuing.

    RATIONALE:  There are four reasons why a queue will form
for the logical channel or control unit.  This exception
identifies when the percent of I/O delayed by queuing is
excessive.  The four reasons, identified in the indicated
exceptions, used to calculate this percentage are listed
below:

     o  Physical channel busy  (Exception 02101)
     o  Logical busy           (    "     02102)
     o  Control unit busy      (    "     02103)
     o  Device busy            (    "     02104)

    DEFINITION:  This exception is detected when the percent
of I/O operations deferred exceeds the installation defined
maximum.

    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:

**  02105 LOG CHAN /LCU DELAYED I/O (ALL REASONS) EXCEEDS MAX
*;
DELAYED=SUM(OF LCAPCPBC, LCAPCLBC, LCAPCCUB, LCAPCDVB);
IF DELAYED > percent
 THEN DO;
   EXCCODE='02105'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
   IF RMFVER<='08 ' THEN DO;
    EXCDESC1='LOGCHAN DELAYED I/O (ALL REASONS) EXCEEDS MAX';
    EXCDESC2='DELAYED=' || PUT(DELAYED,5.1) ||
        '%, LOG. CHAN=' || PUT(LOGCHAN,3.);
   END;
   ELSE DO;
    EXCDESC1='LCU DELAYED I/O (ALL REASONS) EXCEEDS MAX';
    EXCDESC2='DELAYED=' || PUT(DELAYED,5.1) ||
            '%, LCUID=' || LCUID;
   END;
  LINK HIT;
END;

    THRESHOLD MODIFICATION:  The user should modify the
percent value according to the following convention:

    percent - The maximum percent of time an I/O is delayed
is specified.  A threshold of 75 percent would appear as:

    DELAYED > 75