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authorChristoph Hellwig <hch@lst.de>2016-03-04 22:46:17 +0300
committerJ. Bruce Fields <bfields@redhat.com>2016-03-18 18:42:53 +0300
commitf99d4fbdae6765d0bb4ed5441f6fa1f036122d59 (patch)
treeb2192caa11508d5107d2eea3be55c0ec68118e6c /Documentation/filesystems/nfs
parent368248eeb14d08823f1b53de83debd5fd6c108d2 (diff)
downloadlinux-f99d4fbdae6765d0bb4ed5441f6fa1f036122d59.tar.xz
nfsd: add SCSI layout support
This is a simple extension to the block layout driver to use SCSI persistent reservations for access control and fencing, as well as SCSI VPD pages for device identification. For this we need to pass the nfs4_client to the proc_getdeviceinfo method to generate the reservation key, and add a new fence_client method to allow for fence actions in the layout driver. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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+
+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).