Concurrent mode failure

[Former Member]

Hello All. <BR>

I run SAP EP 7.0 on SUN Java SDK 1.4.2_26.<BR>

I have "concurrent mode failure" in java log very often.<BR>

68337.513: [GC 68337.514: [ParNew: 391873K->130816K(392448K), 7.4904532 secs] 2344905K->2216563K(3014912K), 7.4910130 secs]<BR>

68348.738: [GC 68348.738: [ParNew: 392448K->130816K(392448K), 7.4296165 secs] 2478195K->2349900K(3014912K), 7.4301873 secs]<BR>

68360.159: [GC 68360.160: [ParNew: 392448K->118557K(392448K), 7.6382380 secs] 2611532K->2467563K(3014912K), 7.6387969 secs]<BR>

68371.590: [GC 68371.591: [ParNew: 380189K->130816K(392448K), 7.4497681 secs] 2729195K->2569702K(3014912K), 7.4503172 secs]<BR>

68382.937: [GC 68382.938: [ParNew (promotion failed): 392448K->392448K(392448K), 22.3198666 secs]

68405.258: [CMS68414.474: [CMS-concurrent-mark: 28.298/80.683 secs]<BR>

(concurrent mode failure): 2528895K->2363051K(2622464K), 66.5178202 secs] 2831334K->2363051K(3014912K), 88.8385694 secs]<BR>

68472.837: [GC [1 CMS-initial-mark: 2363051K(2622464K)] 2448031K(3014912K), 0.6174037 secs]<BR>

68473.455: [CMS-concurrent-mark-start]<BR>

68475.990: [GC 68475.990: [ParNew: 261632K->128407K(392448K), 6.1581306 secs] 2624683K->2491459K(3014912K), 6.1586733 secs]<BR>

68485.585: [GC 68485.585: [ParNew: 390039K->130816K(392448K), 7.0108027 secs] 2753091K->2622905K(3014912K), 7.0114025 secs]<BR>

68496.017: [Full GC 68496.018: [ParNew: 392448K->392448K(392448K), 0.0001812 secs]<BR>

68496.018: [CMS68514.594: [CMS-concurrent-mark: 27.948/41.138 secs]<BR>

(concurrent mode failure): 2492089K->2622463K(2622464K), 81.4772199 secs] 2884537K->2720850K(3014912K), [CMS Perm : 269874K->269828K(786432K)], 81.4785433 secs]<BR>

68579.509: [GC [1 CMS-initial-mark: 2622463K(2622464K)] 2888804K(3014912K), 2.0011360 secs]<BR>

68581.511: [CMS-concurrent-mark-start]<BR>

68591.857: [Full GC 68591.858: [ParNew: 392448K->392448K(392448K), 0.0001915 secs]68591.858: [CMS68610.677: [CMS-concurrent-mark: 29.159/29.166 secs]<BR>

(concurrent mode failure)[Unloading class jsp._sapportalsjsp_wideNarrow]<BR>

[Unloading class jsp._sapportalsjsp_WAandNavPanel]<BR>

: 2622463K->2622463K(2622464K), 83.0276983 secs] 3014911K->2730400K(3014912K), [CMS Perm : 269836K->269772K(786432K)], 83.0290030 secs]<BR>

68676.899: [GC [1 CMS-initial-mark: 2622463K(2622464K)] 2886721K(3014912K), 2.0034195 secs]<BR>

68678.903: [CMS-concurrent-mark-start]<BR>

68689.929: [Full GC 68689.930: [ParNew: 392448K->392448K(392448K), 0.0001904 secs]<BR>

68689.930: [CMS68708.697: [CMS-concurrent-mark: 29.786/29.793 secs]<BR>

(concurrent mode failure): 2622464K->2622463K(2622464K), 85.5185985 secs] 3014912K->2916245K(3014912K), [CMS Perm : 269782K->269781K(786432K)], 85.5199161 secs]<BR>

68776.740: [GC [1 CMS-initial-mark: 2622463K(2622464K)] 2936154K(3014912K), 2.1820852 secs]<BR>

68778.923: [CMS-concurrent-mark-start]<BR>

68785.744: [Full GC 68785.745: [ParNew: 392447K->392447K(392448K), 0.0002182 secs<BR>

]68785.746: [CMS68808.847: [CMS-concurrent-mark: 29.910/29.923 secs]<BR>

(concurrent mode failure)[Unloading class sun.reflect.GeneratedConstructorAccessor1907]<BR>

: 2622464K->2622463K(2622464K), 91.0097509 secs] 3014911K->2959122K(3014912K), [CMS Perm : 269900K->269881K(786432K)], 91.0111660 secs]<BR>

68878.130: [GC [1 CMS-initial-mark: 2622463K(2622464K)] 2977048K(3014912K), 2.4666378 secs]<BR>

68880.597: [CMS-concurrent-mark-start]<BR>

68883.985: [Full GC 68883.986: [ParNew: 392447K->392447K(392448K), 0.0001916 secs]<BR>

68883.986: [CMS68910.488: [CMS-concurrent-mark: 29.884/29.891 secs]<BR>

(concurrent mode failure)[Unloading class sun.reflect.GeneratedConstructorAccessor1909]<P>

My Java parameters are:<P>

-Xms3072M<BR>

-Xmx3072M<BR>

-XX:+CMSClassUnloadingEnabled<BR>

-XX:+CMSPermGenSweepingEnabled<BR>

-XX:+DisableExplicitGC<BR>

-XX:+HandlePromotionFailure<BR>

-XX:+PrintGCDetails<BR>

-XX:+PrintGCTimeStamps<BR>

-XX:+UseCMSInitiatingOccupancyOnly<BR>

-XX:+UseConcMarkSweepGC<BR>

-XX:+UseParNewGC<BR>

-XX:CMSInitiatingOccupancyFraction 60<BR>

-XX:MaxNewSize 511m<BR>

-XX:MaxPermSize 768M<BR>

-XX:NewSize 511m<BR>

-XX:ParallelGCThreads 8<BR>

-XX:PermSize 768M<BR>

-XX:SoftRefLRUPolicyMSPerMB 1<BR>

-XX:SurvivorRatio 2<BR>

-XX:TargetSurvivorRatio 90<P>

Any suggestions?<BR>

Thanks in advance<BR>

Edited by: Aleksey Barbashin on Jun 16, 2010 9:13 AM

[Former Member]

You are not sized correctly, try this, replace the lines that I have listed.

-Xss2m

-Xms3072M

-Xmx3072M

-XX:MaxNewSize=512M

-XX:NewSize=512M

-XX:+DisableExplicitGC

-XX:MaxPermSize=256M

-XX:PermSize=256M

-XX:SurvivorRatio=2

-XX:TargetSurvivorRatio=90

Perm size should be a lot less than new. Let me know.

[Former Member]

Could you share the solution? I'm getting the same error messages.

Thanks.

[Former Member]

Hello,

You can have some possible reasons for "Concurrent mode failure":

1. Java memory is incorrectly sized.

2. Incorrectly written customer application.

3. Heavy load.

(I had all of them).

For reason 1 I used the following links and sized my memory accordingly:

https://service.sap.com/sap/support/notes/723909

http://legacy.basis.com/support/tips/gc_recommendations.html

http://www.petefreitag.com/articles/gctuning/

http://www.oracle.com/technetwork/java/javase/gc-tuning-6-140523.html

http://cybergav.in/2009/09/22/how-to-deal-with-concurrent-mode-failures-in-the-hotspot-jvm/

For reason 2 I used SAP memory analyzer tool to find incorrectly written customer application

https://wiki.sdn.sap.com/wiki/display/Java/Java+Memory+Analysis

Note 1004255 - How to create a full HPROF heap dump of J2EE Engine 6.40/7.0

http://scn.sap.com/people/krum.tsvetkov/blog/2007/07/02/finding-memory-leaks-with-sap-memory-analyze...

http://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/40244428-5703-2a10-17af-9e878922f...

SAP MAT tool helped me to find application that used enormous amount of memory. This application was rewritten.

For reason 3 I installed 4 additional SAP Java application servers and web dispatcher in front of it.

That helped me to distribute the heavy load.

If You have some additional questions please ask.

[anja_engelhardt2]

moved to SAP NetWeaver Application Server by moderator

[Former Member]

Hi Aleksey,

The most common cause of this exception is lack of enough memory space. Without enough memory the garbage collector wont be able to work properly Check the heap size allocation.

Also for more details check this link:

[Concurrent Mode Failure |;

Regards,

Shyam.