Enhanced performance and scalability In Exchange 2016
The search architecture has been reevaluated and redesigned, in Exchange 2016.
Earlier, search used to be a synchronous operation which was not robust to fault-tolerance.
This new architecture is improved to handle asynchronous and decentralized operations. It distributes the work over multiple servers and keeps retrying in case any servers found to be too busy. This implies that much better reliability and faster results are returned.
Moreover, in this new architecture, the search scalability is improved and enhanced. The multiple numbers of mailboxes can be search upon at once using the console. This has increased the processing capacity from 5k to 10k mailboxes. User can also search an unlimited number of mailboxes while using the Exchange Management Shell.