path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 19:50:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 19:50:32 -0700
commit8b306a2e7c8b23d65682fd70d861e2ba2ae10926 (patch)
tree287e981e27465a1cce4830b548842229d9c03208 /Documentation
parentMerge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild (diff)
parentnfsd: use short read as well as i_size to set eof (diff)
Merge tag 'nfsd-4.6-1' of git://linux-nfs.org/~bfields/linux
Pull more nfsd updates from Bruce Fields: "Apologies for the previous request, which omitted the top 8 commits from my for-next branch (including the SCSI layout commits). Thanks to Trond for spotting my error!" This actually includes the new layout types, so here's that part of the pull message repeated: "Support for a new pnfs layout type from Christoph Hellwig. The new layout type is a variant of the block layout which uses SCSI features to offer improved fencing and device identification. Note this pull request also includes the client side of SCSI layout, with Trond's permission" * tag 'nfsd-4.6-1' of git://linux-nfs.org/~bfields/linux: nfsd: use short read as well as i_size to set eof nfsd: better layoutupdate bounds-checking nfsd: block and scsi layout drivers need to depend on CONFIG_BLOCK nfsd: add SCSI layout support nfsd: move some blocklayout code nfsd: add a new config option for the block layout driver nfs/blocklayout: add SCSI layout support nfs4.h: add SCSI layout definitions
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diff --git a/Documentation/filesystems/nfs/pnfs-scsi-server.txt b/Documentation/filesystems/nfs/pnfs-scsi-server.txt
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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).