4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 01213: Device I/O (Queue + Service) Time Exceeds Max

01213: Device I/O (Queue + Service) Time Exceeds Max

FILE: Device Activity File
SAS FILE NAME: DAYS.HARDVA01
SOURCE LOCATION: prefix.MICS.USER.SOURCE(DYRMFEXC)

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

PURPOSE:  Identify potential device I/O bottlenecks resulting
from excessive I/O (queue wait and service) time.

RATIONALE:  The average I/O time is the sum of the estimated
I/O queue wait time and I/O service time, and thus it
estimates the total time spent per I/O to each device.  The
identified devices should be examined further to determine
the cause.

DEFINITION:  This exception is detected when the average I/O
time exceeds the installation-defined maximum and the number
of I/Os per hour also exceeds an installation-defined
minimum.

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:

** 01213 DEVICE I/O (QUEUE + SERVICE) TIME EXCEEDS MAX;
*;
IOTIME=SUM(Q_TIME,S_TIME);
IF IOTIME GT iotime
 THEN DO;
    EXCCODE='01213'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
    EXCDESC1='DEVICE I/O (QUEUE + SERVICE) TIME EXCEEDS MAX';
    EXCDESC2='I/O TIME (SS.TTT)=' !! PUT(IOTIME,6.3)  !!
                         ', VOL=' !! VOLSER           !!
                        ', ADDR=' !! PUT(DEVNUM,HEX4.)!!
                        ', TYPE=' !! DEVTYPE;
    LINK HIT;
END;

THRESHOLD MODIFICATION:  The user should modify the I/O time
value according to the following convention:

iotime - The maximum I/O time in seconds is specified.  A
.030 second threshold would appear as:

IOTIME GT .030