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IC69405: After applying FP2 on V9.7 on Linux, autonomic backup causes system hang if there are a large number of tablespaces.

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APAR status

  • Closed as program error.

Error description

  • Problem description :
    After applying FP2 on V9.7 on Linux, autonomic backup does not
    function under some circumstances. The degree of parallelism
    chosen in FP2 when taking a full backup now equals the number of
    tablespaces the customer has, without concern for the system
    resources.  As a  result when taking a full non-ITP backup with
    a large number of tablespaces the degree of parallelism chosen
    will cause too many db2bm Processes to be generated resulting in
    possible poorer performance or even a system hang.
    
    The db2diag.log file shows hundreds of
    the following entries:
    
    
    2010-05-31-13.56.35.754214+120 I4003620A486      LEVEL: Info
    PID    : 4784           TID  : 2203100113232 PROC :db2sysc 0
    INSTANCE: db2inst1      NODE : 000            DB  :SAMPLE
    APPHDL  : 0-17          APPID: *LOCAL.db2inst1.100531115629
    AUTHID  : db2inst1
    EDUID  : 674          EDUNAME: db2bm.18.492 (SAMPLE)  0
    FUNCTION: DB2 UDB, database utilities, sqluOpenQueue, probe:225
    MESSAGE : Opening message queue
    DATA #1 : Hex integer, 4 bytes
    0x022B0011
    
    
    2010-05-31-13.56.35.809273+120 E4004107A549  LEVEL: Error(OS)
    PID    : 4784           TID  : 2203779590480PROC :db2sysc 0
    INSTANCE: db2inst1      NODE : 000           DB  :SAMPLE
    APPHDL  : 0-17          APPID: *LOCAL.db2inst1.100531115629
    AUTHID  : db2inst1
    EDUID  : 773           DUNAME: db2bm.18.303 (SAMPLE) 0
    FUNCTION: DB2 UDB, oper system services, sqloCSemCreate, probe:1
    MESSAGE : ZRC=0x8300001C=-2097151972
    CALLED  : OS, -, unspecified_system_function
    OSERR  : ENOSPC (28) "No space left on device"
    
    It creates lot of db2bm processes,until number of semaphores or
    message queues is exhausted.  Then the system hangs. Seems to
    create a db2bm for each tablespace, and customer has many
    hundred tablespaces, So it is that in 9.7 FP2 that the autonomic
    backup tuning for some reason chooses parallelism=number of
    tablespaces.
    
    Setting  DB2_ITP_LEVEL=0 made no difference.
    A db2_kill had to be issued to stop the system.
    

Local fix

  • Workround the issue by adding parallelism to the backup command.
    
    Example:
    
    "backup db <dbname> online use tsm parallelism 4" .
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Users prior to DB2 V97 FP x.                                 *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * Will update later                                            *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Will update later                                            *
    ****************************************************************
    

Problem conclusion

  • Will update later
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC69405

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-06-23

  • Closed date

    2010-09-23

  • Last modified date

    2012-02-16

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

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

    IC70403

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSY

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC69405

Modified date: 16 February 2012