It's multivariate calculus. Also, you have plan ahead and over-allocate or deal with fixed indexes/datasets. You also have to religiously monitor the garbage

It's multivariate calculus. Also, you have plan ahead and over-allocate or deal with fixed indexes/datasets. You also have to religiously monitor the garbage collection and deduce what's going on with search & indexing performance. When the situation changes you need to scale your cluster and re-index everything, which is not a trivial thing at most companies. I've seen bad situations at companies where it takes days to re-index a cluster and they're dead in the water until it's done. And that's just the operations side. You have to make sure your data is flat (because nesting creates subindexes for Lucene and kills your search performance), that you only define in your index template the fields that you want to be searchable (and binary blob the rest), etc.