we have SP 2013 production environment with search items approximately 6 Million.
We are planning to do index partition once search items reach 10 Million items.
We are having topology with two Search servers and all components (admin, content processing, crawl, index, query components) configured in both search servers.
Search index partition is zero and search index primary component is on server 1 and replica on server 2.
My question is, for creating new search index partition, are we able to do it in the existing servers with adding separate disk space for new partition or do we need to go for additional/new SP servers with extending the existing search topology?