IV71203: HIGH CPU GENERATED BY SITUATION ON THE LINUX FILE INFORMATION ATTRIBUTE GROUP

IBM Tivoli Monitoring 6.3.0 Fix Pack 5 (6.3.0-TIV-ITM-FP0005)
IBM Tivoli Monitoring: Linux(R) OS Agent 6.3.0.4-TIV-ITM_LINUX-IF0002

APAR status

• Closed as program error.

Error description

• Problem:
  High CPU  in the klzagent process can be generated by
   situations on the Linux File Information attribute group
   when the predicate contains conditions on the "Checksum" or
   the "File_Content_Changed" attributes, and a very big file is
   present in one of the paths specified in the situation, or
   under the default root path ("/").
  
   Files that are hundreds megabytes large can require several
   seconds for their checksum to be computed.  In this timeframe
   the agent reaches 100% CPU utilization on a single processor.
  
  Affected Platforms / Versions:
   Only 6.30 FP4 and 6.30 FP4 IF1
  
  Diagnostics:
   set (UNIT:klz20 ALL) (UNIT:icc ALL) in KBB_RAS1.
   Search for a great timestamp gap between entry and exit in
   GetDigest function.
  
  Initial Impact:
   High, agent appears to be hanging and business applications on
   the server may be impacted.
  
  Additional Keywords:
   LNXFILE.HASHSUM, LNXFILE.FCCHANGED,
   Linux_File_Information.Checksum,
   Linux_File_Information.File_Content_Changed
  

Local fix

Problem summary

• LINUX File Information can generate high cpu by situations whose
   predicate contains conditions on the "Checksum" or the
  "File_Content_Changed" attributes and a very big file is present
   in one of the paths specified in the situation, or under the
  default root path ("/").  Files that are hundreds megabytes
  large can require several seconds for their checksum to be
  computed.  In this timeframe, the agent reaches 100% CPU
  utilization on a single processor.  The CPU spike and its
  duration is comparable to that produced by external commands
  like "cksum" run on the same files.  The agent performs this
  computation for all the files under the paths specified in the
  situation and under the root path.
  
  In order for this APAR to be properly implemented in your
  environment, a new environment variable has been added.  See the
  "Install Actions" section of the APAR conclusion for more
  details.
  

Problem conclusion

• Install Actions:
  ----------------
  A new environment variable, KLZ_CHECKSUM_LIMIT, has been
  introduced to limit the size of files to which the checksum
  algorithm can be applied.  Default value is 10 (MBytes).  Value
  0 means "unlimited".
  
  
  The fix for this APAR is contained in the following maintenance
  packages:
  
     | fix pack | 6.3.0-TIV-ITM-FP0005
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  ITM AGENT LINUX

• Fixed component ID

  5724C04LN

Applicable component levels

• R630 PSY

     UP