High disk watermark exceeded even when there is not much data in my index

Question

I'm using elasticsearch on my local machine. The data directory is only 37MB in size but when I check logs, I can see:

[2015-05-17 21:31:12,905][WARN ][cluster.routing.allocation.decider] [Chrome] high disk watermark [10%] exceeded on [h9P4UqnCR5SrXxwZKpQ2LQ][Chrome] free: 5.7gb[6.1%], shards will be relocated away from this node

Quite confused about what might be going wrong. Any help?

Answer 1

From Index Shard Allocation:

... watermark.high controls the high watermark. It defaults to 90%, meaning ES will attempt to relocate shards to another node if the node disk usage rises above 90%.

The size of your actual index doesn't matter; it's the free space left on the device which matters.

If the defaults are not appropriate for you, you've to change them.

Answer 2

To resolve the issue in which, the log is recorded as:

high disk watermark [90%] exceeded on [ytI5oTyYSsCVfrB6CWFL1g][ytI5oTy][/var/lib/elasticsearch/nodes/0] free: 552.2mb[4.3%], shards will be relocated away from this node

You can update the threshold limit by executing following curl request:

curl -XPUT "http://localhost:9200/_cluster/settings" \
 -H 'Content-Type: application/json' -d'
{
  "persistent": {
    "cluster": {
      "routing": {
        "allocation.disk.threshold_enabled": false
      }
    }
  }
}'