4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 02150: Average Queue Length Exceeds Max

02150: Average Queue Length Exceeds Max

FILE: Logical Control Unit Activity File
SAS FILE NAME: DAYS.SCPLCU01
SOURCE LOCATION: prefix.MICS.USER.SOURCE(DYRMFEXC)

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

PURPOSE:  Identify logical control units with excessive I/O
queuing.

RATIONALE:  I/O operations queued at the logical control unit
level indicate a possible I/O bottleneck, resulting in lower
throughput or elongated response times in I/O-sensitive
online systems.

DEFINITION:  This exception is detected when the average
queue of waiting I/O operations 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:

/* ******************************************
**  02150 AVERAGE QUEUE LENGTH EXCEEDS MAX **
****************************************** */
IF LCUAVQL GT queue-length
 THEN DO;
  EXCCODE='02150'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
  EXCDESC1='AVERAGE QUEUE LENGTH EXCEEDS MAX';
  EXCDESC2='Q TIME=' !! PUT(LCUAVQL,5.3) !!
          ', LCUID=' !! LCUID;
  LINK HIT;
END;

THRESHOLD MODIFICATION:  The user should modify the value of
queue-length according to the following convention:

queue-length - The maximum I/O queue length is specified.  A
queue length threshold of 5 would appear as:

LCUAVQL GT 5