747efa5b_on_Windows_and_Exchange_Server__Requirement
[Component] Disk space [Notes] The minimum space requirements detailed here don’t account for disk subsystem requirements for adequate performance. [Requirement] 
At least 1.2 GB on the drive on which you install Exchange An additional 500 MB of available disk space for each Unified Messaging (UM) language pack that you plan to install 200 MB of available disk space on the system drive A hard disk that stores the message queue database on an Edge Transport server or Hub Transport server with at least 500 MB of free space
Exchange 2013 Configuration details | Repository of my experience on Windows and Exchange Server
Requirement