Browse Prior Art Database

Generating Symptom Strings for AIX System Dumps

IP.com Disclosure Number: IPCOM000116622D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 103K

Publishing Venue

IBM

Related People

Shaffer, JJ: AUTHOR

Abstract

Disclosed is a method for generating symptom strings from an AIX* system dump.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Generating Symptom Strings for AIX System Dumps

      Disclosed is a method for generating symptom strings from an
AIX* system dump.

      Currently much effort is spent on duplicate problems.  About 45
percent of AIX problems are duplicates.  While certainly not all
these involve a system dump, we can assume that a high percentage of
those that do are also duplicates.  Furthermore, it is difficult for
someone not experienced in dump reading to determine whether or not a
dump represents a duplicate problem.  By describing the problem that
caused the dump symptomatically, it is made much simpler.

      This method describes how symptom strings are generated from
AIX system dumps.  It does not describe symptom strings themselves.

      Working with the System Dump and Error Log: - In AIX, symptom
strings are supported by the system error logging facility.  Symptom
strings can be generated by application or system code.  They are
then put into the error log.

      The difficulty presented here is that it is not advisable to
log the symptom string when the system crashes, i.e., at system dump
time.  The code necessary to generate the symptom string would have
to be part of the pinned kernel, i.e., it would always be memory
resident.  It is important that the kernel be as small as possible.
Therefore the symptom string is automatically generated when the
system reboots.  Unfortunately, this means that some dumps will not
have symptom strings generated because the dumps can not be accessed
upon reboot.  If a dump was not taken, was not able to be written, or
was not successfully copied from paging space at boot time, then we
will not be able to automatically generate a symptom string for that
dump.  Also, no symptom string is generated if the dump was copied to
removable media such as a tape.  However, the facility that generates
the symptom string is part of the AIX dump formatter, the "crash"
command, so a symptom string can easily be manually generated for any
dump at any time.

The steps used to automatically generate a symptom string are as
follows:
  1.  The system crashes, takes a dump and is rebooted.
  2.  If the dump was to paging space it is copied to the file system
       or removable media.
  3.  When the error daemon starts, an error log entry is generated
       giving the status of the dump.
  4.  An error notification method is kicked off by the error daemon
       and uses crash to read the dump and generate the symptom
string.
       The symptom string is written back to the error log.
  5.  Another error notification method could then be used to pick up
       the symptom string and send it to a collector.  Typically the
       collector would be a database lookup facility external to the
       reporting machine.  This feature is planned for AIX Service
       Director.

      Constructing the Symptom String - The sympto...