# GC problems in ES 1.4.4

**URL:** <https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069>\
**Category:** Elasticsearch\
**Created:** [October 13, 2015, 8:52am UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069 "2015-10-13T08:52:46Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![rushi](https://avatars.discourse-cdn.com/v4/letter/r/3bc359/32.png) [@rushi](https://discuss.elastic.co/u/rushi)\
**Post date:** [October 13, 2015, 8:52am UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/1 "2015-10-13T08:52:46Z")

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Frequent full GC even if the memory utilization is 30-40%. We have not changed the default JVM settings

Cluster details -  
a. One master node, 2 data nodes(15 GB Heap size)  
b. All the replicas are allocated on one node and all the primaries are on the other node. It should not be a problem, right? Also frequent full GC is observed on one of the 2 data nodes.  
c. Shards - 75 shards with replication as 1. I guess the problem is because of shard over allocation. Most of the queries we hit are aggregation queries.  
d. mlockall is set to true

Thanks, Rushiraj

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**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 13, 2015, 9:30am UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/2 "2015-10-13T09:30:23Z")

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What do the GC logs show?

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**Author:** ![rushi](https://avatars.discourse-cdn.com/v4/letter/r/3bc359/32.png) [@rushi](https://discuss.elastic.co/u/rushi)\
**Post date:** [October 13, 2015, 12:09pm UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/3 "2015-10-13T12:09:46Z")

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GC logs snippet -  
493999.583: [Full GC493999.583: [CMS: 1308461K-\>1310104K(15047104K), 2.6996450 secs] 1534368K-\>1310104K(15660544K), [CMS Perm : 83967K-\>83967K(83968K)], 2.6998090 secs] [Times: user=2.75 sys=0.00, real=2.70 secs]

As you can see, full gc is getting triggered for heap utilization as low as 1308461K. Total heap size is 15047104K. This is happening on one of the two data nodes.

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<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 13, 2015, 8:11pm UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/4 "2015-10-13T20:11:52Z")

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That's an unusual GC log event, is that from ES?

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**Author:** ![rushi](https://avatars.discourse-cdn.com/v4/letter/r/3bc359/32.png) [@rushi](https://discuss.elastic.co/u/rushi)\
**Post date:** [October 13, 2015, 8:45pm UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/5 "2015-10-13T20:45:13Z")

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Yes. It is from ES. The problem is with perm gen memory utilization. I guess that is triggering the full gc.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 11:44pm UTC](https://discuss.elastic.co/t/gc-problems-in-es-1-4-4/32069/6 "2017-07-05T23:44:59Z")

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