| |
| pNFS SCSI layout server user guide |
| ================================== |
| |
| This document describes support for pNFS SCSI layouts in the Linux NFS server. |
| With pNFS SCSI layouts, the NFS server acts as Metadata Server (MDS) for pNFS, |
| which in addition to handling all the metadata access to the NFS export, |
| also hands out layouts to the clients so that they can directly access the |
| underlying SCSI LUNs that are shared with the client. |
| |
| To use pNFS SCSI layouts with with the Linux NFS server, the exported file |
| system needs to support the pNFS SCSI layouts (currently just XFS), and the |
| file system must sit on a SCSI LUN that is accessible to the clients in |
| addition to the MDS. As of now the file system needs to sit directly on the |
| exported LUN, striping or concatenation of LUNs on the MDS and clients |
| is not supported yet. |
| |
| On a server built with CONFIG_NFSD_SCSI, the pNFS SCSI volume support is |
| automatically enabled if the file system is exported using the "pnfs" |
| option and the underlying SCSI device support persistent reservations. |
| On the client make sure the kernel has the CONFIG_PNFS_BLOCK option |
| enabled, and the file system is mounted using the NFSv4.1 protocol |
| version (mount -o vers=4.1). |
