Number of shards on a ElasticSearch node

I have 4 data nodes.And for a given index I had set number of shards=4
What does these numbers in blue boxes means.Why it sums to more than 4?

4 shards, consisting of shard-0, shard-1, shard-2 and shard-3.

Ohh Thank you.
Does having number of shards 4 or 8 make any difference when number is nodes is four.
My index size is 470 GB. For my logging use case there are less number of query and more ingestion.

How much ingest daily? Will it forever be one index, daily indices or ILM for rollover? 470G / 4 sounds big for shard size, the recommendation seems to be 50G.

Daily ingest of 470 GB.
But making it to more than 4 how will it change because finally some of them will be on same node .

Yes, it will allocate more than one shard per node. Your node legend would just look have 2 shard numbers after each node, node-data1: 0 3, node-data2: 1 7, etc.

I don't know what the performance impact it would have in your environment. 4 or 8, really the same amount of data per node, just organized differently. If you're not replicating, recovery time isn't a concern (bigger shards take longer to recover).