I don't have Elasticsearch installed but I'm getting a watermark error

I have received this warning, but I am not even using or installing elasticsearch.
“Elasticsearch nodes disk usage above low watermark
(triggered 19 minutes ago)
There are Elasticsearch nodes in the cluster running out of disk space, their disk usage is above the low watermark. For this reason Elasticsearch will not allocate new shards to the affected nodes. The affected nodes are: [127.0.1.1] Check Disk-based shard allocation | Elasticsearch Guide [master] | Elastic for more details.”

Ubuntu 22.04.5
Graylog version is 6.1.2

Please does anyone know where this notice comes from? Thanks.

It uses the word elastic of all backend storage. So in your case its saying that your datanode machine is running out of storage, what does the storage usage look like on that machine?

Thank you. This graylog is a test log and has a 50GB disk.

/dev/mapper/ubuntu–vg-ubuntu–lv 29G 14G 13G 52%