4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 09003: High Alternate Track Usage

09003: High Alternate Track Usage

    FILE:             VOA Volume Allocation File
    SAS FILE NAME:    DETAIL.VCAVOA01
    SOURCE LOCATION:  prefix.MICS.USER.SOURCE(DYVCAEXC)

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

    PURPOSE:  Identifies when the number of assigned
alternate tracks on a volume exceeds a specified level.

    RATIONALE:  DASD performance can be significantly
degraded when data is stored on an alternate track due to a
defective primary track.  The extra disk access along with
the necessity to reposition the access mechanism will result
in increased data access times.  Also, high assignments of
alternate tracks can be an early indication of a failing disk
assembly.

    DEFINITION:  This exception is detected when the count of
assigned alternate tracks (VOAALNTK) exceeds the specified
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:

/*---------------------------------------------------------*/
/*                                                         */
/*  09003                                                  */
/*  HIGH ALTERNATE TRACK USAGE                             */
/*                                                         */
/*---------------------------------------------------------*/
IF VOANOATK GT #usedalt
 THEN DO;
  EXCCODE='09003'; SEVERITY='W'; MGMTAREA='PERFORMANCE';
  EXCDESC1='HIGH ASSIGNMENT OF ALTERNATE TRACKS';
  EXCDESC2='ALTERNATE TRACKS USED=' || PUT(VOANOATK,3.) ||
           ', VOL=' || VOLSER;
  LINK HIT;
END;

    THRESHOLD MODIFICATION:  The user should modify the
#usedalt value according to the following conventions:

    #usedalt -  The maximum acceptable number of assigned
         alternate tracks.  A maximum count of 5 would appear
         as:

         VOANOATK GT 5