# Elastic Master nodes cluster heap usage **URL:** \ **Category:** Elasticsearch\ **Created:** [October 8, 2018, 9:54am UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426 "2018-10-08T09:54:19Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Zerobot](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zerobot/32/48977_2.png) [@Zerobot](https://discuss.elastic.co/u/Zerobot)\ **Post date:** [October 8, 2018, 9:54am UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/1 "2018-10-08T09:54:19Z")
Hello, In our Elasticsearch cluster we have 3 master nodes. I've noticed that from time to time one of them is under a heavy load while the other two seem to be doing nothing. Is that normal for elastic master nodes or is that a sign of something bad? It looks like this in Cerebro: ![elastic_heap](https://us1.discourse-cdn.com/elastic/original/3X/f/c/fc5e41746f38d51794a62134f103cfd7918be331.png) ---
**Author:** ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)\ **Post date:** [October 8, 2018, 10:14am UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/2 "2018-10-08T10:14:29Z")
Without the column headings it's a little hard to be sure what these numbers mean. However, Elasticsearch does elect a single master-eligible node to be in charge of the cluster and this elected node does perform a lot more work than the other master-eligible ones, so this kind of mismatch seems reasonable to me. ---
**Author:** ![Zerobot](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zerobot/32/48977_2.png) [@Zerobot](https://discuss.elastic.co/u/Zerobot)\ **Post date:** [October 8, 2018, 11:03am UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/3 "2018-10-08T11:03:06Z")
Sadly, it is not the "master of masters" that is under heavy load. ![elastic_heap_2](https://us1.discourse-cdn.com/elastic/original/3X/6/0/609e69df448a2aec79c6a7992d946888cd937149.png) ---
**Author:** ![Zerobot](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zerobot/32/48977_2.png) [@Zerobot](https://discuss.elastic.co/u/Zerobot)\ **Post date:** [October 8, 2018, 11:14am UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/4 "2018-10-08T11:14:35Z")
That's how HEAP USAGE of that specific node looks in Kibana's monitoring: ![heap](https://us1.discourse-cdn.com/elastic/original/3X/9/a/9a4a65e5fb99eb26c57a6e2f0e303c10b91c51de.png) Two other master nodes, including the "master of masters": ![heap1](https://us1.discourse-cdn.com/elastic/original/3X/c/b/cb2bc5d3777363100128b4a029b8e578c407d4ec.png) ![heap2](https://us1.discourse-cdn.com/elastic/original/3X/9/c/9c5403d5245ba3aaa781d80f652ea5cd75d8d4a8.png) ---
**Author:** ![Zerobot](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zerobot/32/48977_2.png) [@Zerobot](https://discuss.elastic.co/u/Zerobot)\ **Post date:** [October 8, 2018, 12:17pm UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/5 "2018-10-08T12:17:05Z")
I think i found the problem. Garbage Collector on that "strange" node. Had to correct JVM settings on that one node. Problem solved. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [November 5, 2018, 12:17pm UTC](https://discuss.elastic.co/t/elastic-master-nodes-cluster-heap-usage/151426/6 "2018-11-05T12:17:05Z")
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