# For an I/O block on a machine in the ES cluster, how can I set it so that ES returns a 504 timeout and then tries to poll the node to retry

**URL:** <https://discuss.elastic.co/t/for-an-i-o-block-on-a-machine-in-the-es-cluster-how-can-i-set-it-so-that-es-returns-a-504-timeout-and-then-tries-to-poll-the-node-to-retry/268857>\
**Category:** Elasticsearch\
**Created:** [March 31, 2021, 2:59am UTC](https://discuss.elastic.co/t/for-an-i-o-block-on-a-machine-in-the-es-cluster-how-can-i-set-it-so-that-es-returns-a-504-timeout-and-then-tries-to-poll-the-node-to-retry/268857 "2021-03-31T02:59:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![serug](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/serug/32/86361_2.png) [@serug](https://discuss.elastic.co/u/serug)\
**Post date:** [March 31, 2021, 2:59am UTC](https://discuss.elastic.co/t/for-an-i-o-block-on-a-machine-in-the-es-cluster-how-can-i-set-it-so-that-es-returns-a-504-timeout-and-then-tries-to-poll-the-node-to-retry/268857/1 "2021-03-31T02:59:28Z")

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I have a question to ask .  
The scenario is that one of the machines in my ES(6.7) cluster is blocked by I/O, which causes the ES request to be blocked as well, thus causing the thread pool resource depletion. I would like to ask whether there is a corresponding solution for this scenario. When I check the source code（RestClient.java）, I see that there is a logic to poll cluster nodes, but only for 502,503,504 response code to perform the retry mechanism, but when I/O block, is there a corresponding timeout setting, so that ES can return 504 response code?  
Thanks

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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:** [April 28, 2021, 2:59am UTC](https://discuss.elastic.co/t/for-an-i-o-block-on-a-machine-in-the-es-cluster-how-can-i-set-it-so-that-es-returns-a-504-timeout-and-then-tries-to-poll-the-node-to-retry/268857/2 "2021-04-28T02:59:44Z")

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