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| Does Garbage Collection (GC) trigger JVM restart? |
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| EricL |
 Posted: Wed Apr 04, 2018 11:48 am Post subject: Does Garbage Collection (GC) trigger JVM restart? |
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Centurion
Joined: 10 Oct 2014
Posts: 102
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Hi,
1. We have a cluster (with 2 JVMs) created on Websphere Application Server(V8.0.0.12)
2. Yesterday morning, one of the JVMs (call it JVM2) got OutOfMemory(OOM) error started at [April/3/2018 0:18:55:819 AM], the error keep on repeating again and again, until [April/3/2018 9:02:01:438 AM], the last OOM error message was logged, it lasted about 9 hours.
3. After last OutOfMemory(OOM) error message logged at about [April/3/2018 9:02:01:438 AM], we noticed JVM started rebooting:
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[April/3/2018 9:02:18:051 EDT] 00000000 ManagerAdmin I TRAS0017I: The startup trace state is *=info:org.apache.struts.tiles.commands.TilesPreProcessor=off.
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When rebooting done, everything backed to normal....
Question now is: What has been triggered the JVM rebooting? Was it GC?
We've been searching hard trying to find any evidence to prove it is GC triggered the JVM restart, but all logs: systemout.log and FFDC log didn't have any info to support it, so again, question is: does GC trigger JVM restart?
Thanks,
Eric |
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| fjb_saper |
| Posted: Wed Apr 04, 2018 6:41 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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I don't think so. If I had to take a guess I'd say the OOM error triggered it.
If after GC you still get an OOM error there is nothing the JVM can do but reboot. It is also the sign of a probable memory leak. Find it!, Plug it! 
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MQ & Broker admin |
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| EricL |
| Posted: Thu Apr 05, 2018 9:59 am Post subject: |
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Centurion
Joined: 10 Oct 2014
Posts: 102
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Thanks Grand.
Think this is the tricky part of the situation, we noticed JVM restarted, but can not find out what caused it, could be either OOM error or GC, or something else, we just want to get some evidence to confirm it, regardless whatever cause...
Eric |
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| rekarm01 |
| Posted: Thu Apr 05, 2018 4:18 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 1415
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| Acolyte wrote: |
| Thanks Grand. |
A user's name is different from a user's rank.
| Acolyte wrote: |
| we noticed JVM restarted, but can not find out what caused it, could be either OOM error or GC, or something else ... |
By the time a JVM throws an OutOfMemoryError, it has already completed garbage collection. |
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| EricL |
| Posted: Mon Apr 09, 2018 4:01 pm Post subject: |
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Centurion
Joined: 10 Oct 2014
Posts: 102
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Hi,
Just an update, it looks like OutOfMemory caused JVM restart, got logs shown:
1. OOM error today started at: [April/9/2018 0:34:08:084 am], and
2. Last OOM error came in at: [April/9/2018 0:56:55:806 am],
3. At [April/9/18 0:56:56:021 am] noticed TCP Channel TCP_1 has stopped listening on host * (IPv6) port 9061
4. At [April/9/18 0:56:56:790 am] application stopped
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5. [April/9/18 0:57:59:879 am] 00000000 ManagerAdmin I TRAS0017I: The startup trace state is *=info:org.apache.struts.tiles.commands.TilesPreProcessor=off.
JVM starting... |
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