PK42654: CMAS SHUTSDOWN WITH TSPBLK SHORTAGE AND SOS CONDITION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The customer began experiencing short-on-storage conditions in
  his CMAS.  This led to the CMAS shutting down after a EYUXZ0910I
  message due to there being no available TSPBLKs.  CTMB failed
  with pointId 4 CMPI_XCPT_NOTSPBLK in the ACQUIRE_TSPBLK routine.
  This pointID is set if the TRNSPT_FTSPP queue at x'458' into the
  COM MOEB is zeros.
  .
  We ran out of TSPBLKs because the region was running short on
  storage causing Getmain errors.  The EDSALIM was set to 250M and
  ECDSA was at 224M with 201M in subpool SMSHRC31.  Majority of
  this storage was for a CLBA which contains information about the
  link buffers (LBBs).  It showed that there were currently x'F0E'
  LBBs (d'3854') but only 2 of them were currently in use.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICSPlex/SM V3R1M0 Users                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: CMASes that act as hubs for indirect    *
  *                      connections between other CMASes may    *
  *                      experience short-on-storage conditions  *
  *                      in EDSA due to problems with CPSM       *
  *                      communications buffer management.       *
  ****************************************************************
  * RECOMMENDATION: After applying the PTF that resolves this    *
  *                 APAR, all CMASes must be restarted.  Note    *
  *                 that the restarts do not need to occur at    *
  *                 the same time.                               *
  ****************************************************************
  A CMAS uses buffers allocated in EDSA for communicating with
  other CMASes and local MASes.  A CMAS allocates two buffers for
  each CMAS it has a direct connection to, and one buffer to
  communicate with all MASes that connect to it.  No buffers are
  allocated for indirect CMAS connections.
  
  When a CMAS receives data from one CMAS that is directed to
  another CMAS, it must allocate a buffer to handle that request.
  Based upon the amount of data being passed, and the number of
  indirect connections for which this CMAS is a hub, the hub CMAS
  may need to allocate a great number of buffers at one time.
  
  When these extra buffers have been sent, they are usually placed
  on an available queue, with the idea that they may be needed
  eventually for similar requests.  If no requests occur in a
  reasonable period of time, or if a SOS condition exists, CPSM
  communications buffer management is supposed to free available
  buffers, to either avert a future SOS condition, or to help
  relieve an existing SOS condition.  Design issues in both
  aspects of buffer management can lead to SOS conditions, or
  prolong existing SOS conditions.
  

Problem conclusion

• Changes have been made to both aspects of CPSM communications
  buffer management:
  
  -  To help avert SOS conditions, changes have been made to the
     algorithm used to determine how many available buffers can be
     freed when method EYU0CLBC (CLBC) is called at five minute
     intervals in the CMAS.
  
  -  To help relieve SOS conditions, changes have been made to
     module EYU9XLME (XLME) and method EYU0CSGT (CSGT) to ensure
     that CLBC is always called when SOS occurs, and continues to
     be called at 10 second intervals while the SOS condition
     exists.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

• CMASes that act as hubs for indirect
  connections between other CMASes may
  experience short-on-storage conditions
  in EDSA due to problems with CPSM
  communications buffer management.
  
  
  A CMAS uses EDSA buffers for communicating with other CMASes and
  local MASes.  A CMAS allocates two buffers for each CMAS it has
  a direct connection to, and one buffer to communicate with all
  MASes that connect to it.  No buffers are allocated for indirect
  CMAS connections.
  
  When a CMAS receives data from one CMAS that is directed to
  another CMAS, it must allocate a buffer to handle that request.
  Based upon the amount of data being passed, and the number of
  indirect connections for which this CMAS is a hub, the hub CMAS
  may need to allocate a great number of buffers at one time.
  
  When these extra buffers have been sent, they are usually placed
  on an available queue, with the idea that they would be needed
  eventually for similar requests.  If no requests occur in a
  reasonable period of time, or if a SOS condition exists, CPSM
  communications buffer management is supposed to free available
  buffers, to either avert a future SOS condition, or to help
  relieve an existing SOS condition.  Design issues in both
  aspects of buffer management can lead to SOS conditions, or
  prolong existing SOS conditions.
  
  
  Changes have been made to both aspects of CPSM communications
  buffer management:
  
  -  To help avert SOS conditions, changes have been made to the
     algorithm used to determine how many available buffers can be
     freed when method EYU0CLBC (CLBC) is called at five minute
     intervals in the CMAS.
  
  -  To help relieve SOS conditions, changes have been made to
     module EYU9XLME (XLME) and method EYU0CSGT (CSGT) to ensure
     that CLBC is always called when SOS occurs, and continues to
     be called in 10 second intervals while the SOS condition
     exists.
  

APAR Information

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

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

  UK25383 PK45714

Modules/Macros

•    EYUQCLBM EYURCLBF EYURCLBM EYURCOEB EYU0CLBC
  EYU0CLBE EYU0CLCS EYU0CLCT EYU0CLCU EYU0CLER EYU0CLFX EYU0CLMS
  EYU0CLMT EYU0CLMU EYU0CLRR EYU0CLRS EYU0CLRT EYU0CLSS EYU0CLST
  EYU0CSGT EYU0CTRD EYU9XLME
  

Fix information

• Fixed component name

  CPSM CICS 3.1

• Fixed component ID

  5655M1501

Applicable component levels

• R100 PSY UK25383

     UP07/05/25 P F705

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.