Hardware server requirements for a fast ElasticSearch experience on one website with 900k entries

  1. number of processors, or what kind of processors work
    work best for a search-focused site with many records?
  2. how much RAM?

It will depend on the document, query and your response requirements.
It's a good idea to try it out on a laptop at hand. Using docker is a good option. With a sample of a few thousand or tens of thousands of companies, you can estimate how much GB of indexes will be generated per company and calculate the overall storage requirements. From there, you can approximate the rough memory requirements.

This blog will help you.

  1. storage: NVMe SSD?

@rcowart said SATA SSD was as good as NVMe SSD for indexing.