priotizing results from certain sites in elasticsearch

Question

I'm taking my first steps into Elasticsearch to see if I can use it to build a vertical search engine that crawls and indexes a few 1000 websites from a niche. Since I'm new to Elasticsearch I have a few questions:

1. I did a little test with 5 websites and that seems to work but I have not found the maximum number of sites that is allowed. So is there a maximum number of sites allowed?
2. I would like to "tune" the results so that results from certain sites always appear above the results from other sites. Can this be done with Elasticsearch and if so how?

Answer 1

1. There is no hard limit but the more data you put into ES the more hardware (aka expenses) you need.

2. Take a look at the boosting queries. If your boosting factor is high enough for some sites, results from there will be always on top.