This path is linked to Elasticsearch, By doing curl -XGET 'http://localhost:9200/_cat/allocation?v'
you will see the free space available at Elasticsearch.

Total 49.9GB of disk on the root path that mapping df -h
directory /
, 98% of space used.
I cleared a few spaces and it's working now, Have to allocate space or move the project to /DATA where 2.9TB is available.

We have three states on Elasticsearch Disk Watermark, Based on your config file this will show, the Flood state is the one where read_only_allow_delete will be enabled by Elasticsearch
- Low disk watermark
- High disk watermark
- Flood stage disk watermark
PUT _cluster/settings
{
"transient": {
"cluster.routing.allocation.disk.watermark.low": "85%",
"cluster.routing.allocation.disk.watermark.high": "90%",
"cluster.routing.allocation.disk.watermark.flood_stage": "95%",
"cluster.info.update.interval": "1m"
}
}
For more details, you can refer to the link.
https://opster.com/guides/elasticsearch/capacity-planning/elasticsearch-disk-watermark/
https://opster.com/guides/elasticsearch/capacity-planning/elasticsearch-high-disk-watermark/