A split decision surrounds the use of tightly coupled or loosely coupled NAS solutions. Tightly coupled NAS clusters essentially scale as you add nodes. The more nodes you add, the more storage I/O performance you get and, in many cases, you get. The truth is, we don’t know yet. In NAS clusters there are few cases that I have heard of customers hitting the wall. Performance and scale should be the key differentiator. If both methods can hit your performance and capacity needs as far into the future as you can predict.”]
Source: https://www.darkreading.com/database-security/nas-clusters-how-should-you-couple-