# Increased CPU usage on data nodes after Elasticsearch upgrade from 8.8.2 to 8.15.3

**URL:** <https://discuss.elastic.co/t/increased-cpu-usage-on-data-nodes-after-elasticsearch-upgrade-from-8-8-2-to-8-15-3/370184>\
**Category:** Elasticsearch\
**Created:** [November 7, 2024, 8:50pm UTC](https://discuss.elastic.co/t/increased-cpu-usage-on-data-nodes-after-elasticsearch-upgrade-from-8-8-2-to-8-15-3/370184 "2024-11-07T20:50:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![lifer](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/lifer/32/94603_2.png) [@lifer](https://discuss.elastic.co/u/lifer)\
**Post date:** [November 7, 2024, 8:50pm UTC](https://discuss.elastic.co/t/increased-cpu-usage-on-data-nodes-after-elasticsearch-upgrade-from-8-8-2-to-8-15-3/370184/1 "2024-11-07T20:50:53Z")

</div>

Hi!

We are observing 1.5-2x increase in CPU usage after upgrade of our ES cluster from version 8.8.2 to 8.15.3.

Our cluster is hosted on AWS EC2 instances, it consists of 6 nodes: 3 master nodes (c6i.large) and 3 data nodes (c7i.8xlarge).

Load on the cluster is mostly "search" requests from our search & recommendations APIs (no significant indexing is going on).

This is how CPU consumption on data nodes looks before/after upgrade:

 ![Screenshot 2024-11-07 at 10.47.56 PM 1](https://us1.discourse-cdn.com/elastic/original/3X/5/b/5b5d4a7e7d4451400fa21eefe5092bfa5a6b751f.png)

On a " stack monitoring" tab, some weird things I see is a spike on "cgroup" graph:

 ![Screenshot 2024-11-07 at 10.49.19 PM](https://us1.discourse-cdn.com/elastic/original/3X/1/0/10e9352957c24219d33b4c6cdba6f2a4ea7de228.png)

and increase in "request time" for our most used index:

 ![Screenshot 2024-11-07 at 10.59.33 PM](https://us1.discourse-cdn.com/elastic/original/3X/0/4/04a0ba61be866db5e585abdfa88d2ecb4698ce37.png)

Please advise what is the most convenient way to debug this.

Thanks in advance, Alex.