About quiescing the stack

The storage management stack is a layered arrangement of software elements. An I/O request from a database application passes from element to element until a hardware request to move data reaches the storage network. Each stack element performs a variety of functions, some of which treat I/O requests like transactions to assure their completion. Before a snapshot is created, the stack must be quiesced (made transactionally consistent).

Since the file system is the front-line interface to applications for managing files and I/O, file system quiesce is critical to quiescing the stack.