4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 01101: Block Multiplexor Channel Overloaded

01101: Block Multiplexor Channel Overloaded

FILE: Physical Channel Activity File
SAS FILE NAME: DAYS.HARPCA01
SOURCE LOCATION: prefix.MICS.USER.SOURCE(DYRMFEXC)

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

PURPOSE:  Identify overloaded block multiplexor channels
that may be a symptom of I/O problems and performance
degradation.

RATIONALE:  As physical channel-busy increases, the
probability of I/O delay increases exponentially.  It can be
inferred that I/O delay due to channel-busy is occurring from
a high channel-busy situation.  This can be a real problem if
this channel is the path to the page data sets.

DEFINITION:  This exception is detected when the channel-busy
percentage exceeds the installation-defined maximum.  A block
multiplexor channel is overloaded when its channel-busy
percent exceeds 35%.

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:

** 01101 BLOCK MULTIPLEXOR CHANNEL OVERLOADED;
*;
IF CHANTYPE EQ 'BLOCK MPX'
 AND PCAPCBSY GT percent
 THEN DO;
  EXCCODE='01101'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
  EXCDESC1='BLOCK MULTIPLEXOR CHANNEL OVERLOADED';
  EXCDESC2='BUSY=' !! PUT(PCAPCBSY,5.1) !!
        '%, CHAN=' !! CHANNEL;
  LINK HIT;
END;
THRESHOLD MODIFICATION:  The user should modify the percent
value according to the following convention:

percent - The maximum percent channel-busy is specified.  A
35 percent threshold would appear as:

PCAPCBSY GT 35