Storage to RAM

Elastic Stack Elasticsearch
1

From the pricing calculator, I see elastic recommends 1 GB RAM for 30 GB storage (hot data).

for my on prem set up, is it okay if I have 2 data nodes with 5 TB of data each? If I follow the 1:30 rule, number of data nodes increase so much

Please help! I am okay to have 3 dedicated master nodes

2

On Elastic Cloud there are different hardware profiles that generally follow best practices. There is a storage optimised (dense) instance type that offers a 1:80 ratio so 1:30 is specifically for hot data which tend to be quite I/O intensive.

If you are self-hosting you can choose whatever ratio you want and the optimal ratio can vary a lot depending on type of use case, hardware used and performance requirements. The more data you put on each node, the slower querying will generally be unless you specifically target small subsets of indices. I would recommend that you test with your data and queries to see what maximum density works for you.