Exclusive mode on a Windows and NT disk can mean different things for both local and external (SAN) based disk storage. In a nutshell, exclusive mode is used to protect and maintain data integrity for a disk device.
For example, in a clustered or shared access environment, a specific server needs to have exclusive access to a disk or LUN at a time. For NAS or Windows shared storage, the server that has primary attachment to the LUN may have exclusive access to the disk. Another example of exclusive mode is when a maintenance or system tool needs to take exclusive access of a disk or LUN for some specific purpose.
This was first published in October 2005