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ASM Rebalance Poor Performance (Doc ID 1427503.1)

Last updated on JANUARY 30, 2022

Applies to:

Oracle Database - Enterprise Edition - Version 11.1.0.7 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.

Symptoms

1. This issue only happens with 11.1.0.7 ASM as this issue is fixed in 11.1.0.7.1

2. Rebalancing performance is getting slower over time and v$asm_operation.est_rate shows less than 1000 and the value gets decreasing over time.
In some cases, the rebalance is completed in a few days but most of time it fails with ORA-04031 or ORA-00600[723].

Please note that the value of EST_RATE is decreasing from 4505 tp 73 and EST_MINUTES is increasing from 530 to 3081 over time within 5 hours from v$asm_operation view.

Time           G_N Oper   State Power     Actual    Sofar Est_Work Est_Rate Est_Min
Jan 9 10:54:05 1 REBAL RUN      10           10   13312 2439430       4505      530 <<<< Started with 4505
Jan 9 11:01:00 1 REBAL RUN      10           10   32590 2439432       2104    1146
Jan 9 11:30:00 1 REBAL RUN      10           10   71978 2439447        953     2497
Jan 9 12:01:00 1 REBAL RUN      10           10   98256 2439454        710     3322
Jan 9 12:30:00 1 REBAL RUN      10           10   17412 2439437        608     3833
Jan 9 13:01:00 1 REBAL RUN      10           10  135251 2439453       519      4451
Jan 9 13:30:00 1 REBAL RUN      10           10  150034 2439455       478     4793
Jan 9 14:01:00 1 REBAL RUN      10           10  163919 2439470       415     5463
Jan 9 14:30:00 1 REBAL RUN      10           10  169920 2439469       403     5709
Jan 9 14:32:31 1 REBAL RUN      10           10       240   182279       142     1259
Jan 9 15:01:00 1 REBAL RUN      10           10     3720   191643       112     1749
Jan 9 15:30:00 1 REBAL RUN      10           10     5040   196994         73     3081 <<<< Ended with 73



3. The following similar error occurs in ASM alert.log during rebalance.

ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67708
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67651
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67655
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67659
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67881
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67745
ERROR: Releasing group with AU enqueue for extent gn=3 disk=5 au=67718



4. The usage of following resources below from v$sgastat keeps increasing over time during rebalancing.

- shared pool ges resource
- shared pool ges enqueues
- shared pool KFD extent enqueue obj
- shared pool free memory


Please note that "KFD extent enqueue obj" resource started with 5M and ended with 120M and "ges resource" from 4M to 50M over time within 5 hours v$sgastat view.

Jan 9 10:53:00 shared pool KFD extent enqueue obj 5902696
Jan 9 10:54:01 shared pool KFD extent enqueue obj 9011376
Jan 9 10:55:00 shared pool KFD extent enqueue obj 11485624
..
Jan 9 15:49:00 shared pool KFD extent enqueue obj 119863312
Jan 9 15:50:00 shared pool KFD extent enqueue obj 119892440
Jan 9 15:51:00 shared pool KFD extent enqueue obj 119924216
.
.
Jan 9 10:53:00 shared pool ges resource 4095280
Jan 9 10:54:01 shared pool ges resource 5370008
Jan 9 10:55:00 shared pool ges resource 6437088
Jan 9 10:56:00 shared pool ges resource 7354200
..
Jan 9 15:49:00 shared pool ges resource 51479400
Jan 9 15:50:00 shared pool ges resource 51502472
Jan 9 15:51:00 shared pool ges resource 51508240



Cause

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In this Document
Symptoms
Cause
Solution
References


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