We're using Elasticsearch for almost our products and we found a strange issue on our Elasticsearch cluster.
The problem is that the shards are crowded in a node for a couple of indexes.
Please check the above image.
- Elasticsearch version : 5.5
- OS version : CentOS 6.9
- 3 Master Nodes
- 7 Hot Data Nodes
- Shards configuration : 24
- Replica configuration : 0
We've used that 5 data nodes and then recently, we've added 2 data nodes in the clusters.
After then, the shards are crowded in a 6th node.
I can't say that how to reproduce this issue because other indexes are looking good.
Obviously, if we created new indexes then it could occur this issue.
I believe we can resolve this issue if we can relocate the shards manually.
But I worried about occur again after doing that.
So, my questions are,
- Is this a reasonable issue if the additional data nodes are added in exists cluster?
- Is Elasticsearch performance still good if the shards are crowded in a single node?
- If this topic could be an issue, how do we fix it?
Thanks for your help!