Primary Data The Parallel Network File System (pNFS) allows a separation between the metadata (onto a metadata server) and data (onto a storage device) for a file. The flexible file layout type is an extension to pNFS which allows the use of storage devices in a fashion such that they require only a quite limited degree of interaction with the metadata server, using already existing protocols. This document describes two extensions to the flexible file layout type to allow for multiple stateids for tightly coupled NFSv4 models and an additional security mechanism for loosely coupled models.