I am working on a site where we are going to store movies data. Total records will be around 5 million which will require around 7 GB of data. This data will be synced once and eventually few new documents will be added every day. So this is not going to be write heavy application. All this data will be in one index only. 1K QPS is not a estimation but it is derived from our existing hits as we are currently serving search directly from DB. Currently we have 700 QPS and I am just planning ahead by assuming 1000 QPS. Also if I setup 3 nodes with all roles and all data across three nodes then my primary shard will have 2.5 GB data each. Isn't it too low for a single primary shard? Also if each data node will have one primary and one replica then it will have 5 GB data on it, so how much disk space should I have total on each?