4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 01214: Critical Device I/O Rate Below Min

01214: Critical Device I/O Rate Below Min

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

SEVERITY: Warning              (SEVERITY='W')
MANAGEMENT AREA: Performance   (MGMTAREA='PERFORMANCE')

PURPOSE:  Identify devices with low I/O rates that may detect
devices with I/O bottlenecks or subsystem failures.

RATIONALE:  A low device I/O rate may reflect I/O bottlenecks
causing degraded performance, during periods when significant
work is expected.  Low I/O rates to specific devices (such as
TSO, IMS, CICS, and other database devices) may also indicate
a subsystem failure or degradation within the subsystem.

DEFINITION:  This exception is detected when the device I/O
rate per hour is less than an installation-defined minimum
for installation-defined time periods.  Different limits may
be specified for different device class and types and even
device addresses or volume serial numbers.

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:

** 01214 CRITICAL DEVICE I/O RATE BELOW MIN;
*;
IF (DEVADDR EQ 'device-address' AND DVAACTRT LT io-rate)
 OR (DEVADDR EQ 'device-address' AND DVAACTRT LT io-rate)
 OR (VOLSER EQ 'volume-serial' AND DVAACTRT LT io-rate)
 AND (DAYNAME EQ 'day' OR DAYNAME EQ 'day'
      OR DAYNAME EQ 'day' OR DAYNAME EQ 'day')
 AND (HOUR GE hh1 AND HOUR LE hh2)
 AND ZONE EQ 'n'
 THEN DO;
  EXCCODE='01214'; SEVERITY='W'; MGMTAREA='PERFORMANCE';
  EXCDESC1='CRITICAL DEVICE I/O RATE BELOW MIN';
  EXCDESC2='I/O RATE=' !! PUT(DVAACTRT,5.1) !!
          '/SEC, VOL=' !! VOLSER            !!
             ', ADDR=' !! PUT(DEVNUM,HEX4.) !!
             ', TYPE=' !! DEVTYPE;
  LINK HIT;
END;
THRESHOLD MODIFICATION:  Modify the values of the following:

o device-address:  the hexadecimal device address is
  specified as a three character SAS literal.  For example,
  device address 1A8 is expressed as:

  DEVADDR EQ '1A8'

o volume-serial:  the volume serial number is specified as a
  one to six character SAS literal.  For example, volume
  serial number PAG1C0 is expressed as:

  VOLSER EQ 'PAG1C0'

o io-rate:  the minimum number of start I/Os to a critical
  device in an hour is specified.  For example, a threshold
  of 1000 for device address 2B3 is expressed as:

  (DEVADDR EQ '2B3' AND DVAACTRT LT 1000)

o day:  the days of the week to be included in the exception.
  Specify the first three characters of each day's name,
  enclosed in quotes and separated with OR's.  For example,
  prime time specified as MONDAY through FRIDAY is expressed
  as:

  (DAYNAME EQ 'MON' OR DAYNAME EQ 'TUE' OR DAYNAME EQ 'WED'
   OR DAYNAME EQ 'THU' OR DAYNAME EQ 'FRI' )

o hh1 and hh2 (time period):  the hour range to be included
  in the exception, where hh1 and hh2 are hours of the day.
  Prime time specified as 8:00 am through 6:59 pm (18:59) is
  expressed as:

  (HOUR GE 8 AND HOUR LE 18)

o n (ZONE value):  the time period to be included. The ZONE
  definition includes the hours and days, so the ZONE
  definition is a simpler method of selecting hours and days
  for processing.  If ZONE 1 corresponds to Monday through
  Friday from 8:00 am until 6:59 pm, it is expressed as:

  ZONE EQ '1'