Indezes and Sharding on Cluster

Elastic Stack Elasticsearch
1

Hi,
in case we expected 300-500gb data per day and we have 4 data nodes in cluster.
We want to create 1 index per day.

How many Shards are wise to split the index off?
4 Shards to balance the load to the 4 Nodes?
8 Shards to balance the load and be sure that 1 Shards doesnt grow much bigger than 50gb?

2

Having all 4 nodes indexing is probably a good idea, so if you aren't replicating, 4 shards would be good. Recommended shard size is 50G, ILM rollover at 200G would automatically manage your shard size as an alternative to daily indices.