Re: [PATCH 14/18] nfsd: pNFS block layout driver
From: J. Bruce Fields <hidden>
Date: 2015-01-06 17:17:00
Also in:
linux-fsdevel, linux-nfs
Possibly related (same subject, not in this thread)
- 2015-01-12 · Re: [PATCH 14/18] nfsd: pNFS block layout driver · Christoph Hellwig <hch@lst.de>
- 2015-01-12 · Re: [PATCH 14/18] nfsd: pNFS block layout driver · Tom Haynes <hidden>
- 2015-01-08 · Re: [PATCH 14/18] nfsd: pNFS block layout driver · J. Bruce Fields <hidden>
- 2015-01-08 · Re: [PATCH 14/18] nfsd: pNFS block layout driver · Jeff Layton <hidden>
- 2015-01-07 · Re: [PATCH 14/18] nfsd: pNFS block layout driver · Christoph Hellwig <hch@lst.de>
On Tue, Jan 06, 2015 at 05:28:37PM +0100, Christoph Hellwig wrote:
quoted hunk ↗ jump to hunk
Add a small shim between core nfsd and filesystems to translate the somewhat cumbersome pNFS data structures and semantics to something more palatable for Linux filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> --- .../filesystems/nfs/pnfs-block-server.txt | 40 +++++ fs/nfsd/Makefile | 2 +- fs/nfsd/blocklayout.c | 194 +++++++++++++++++++++ fs/nfsd/blocklayoutxdr.c | 157 +++++++++++++++++ fs/nfsd/blocklayoutxdr.h | 62 +++++++ fs/nfsd/nfs4layouts.c | 7 + fs/nfsd/pnfs.h | 1 + 7 files changed, 462 insertions(+), 1 deletion(-) create mode 100644 Documentation/filesystems/nfs/pnfs-block-server.txt create mode 100644 fs/nfsd/blocklayout.c create mode 100644 fs/nfsd/blocklayoutxdr.c create mode 100644 fs/nfsd/blocklayoutxdr.hdiff --git a/Documentation/filesystems/nfs/pnfs-block-server.txt b/Documentation/filesystems/nfs/pnfs-block-server.txt new file mode 100644 index 0000000..f45d399 --- /dev/null +++ b/Documentation/filesystems/nfs/pnfs-block-server.txt@@ -0,0 +1,40 @@ +pNFS block layout server user guide + +The Linux NFS server now supports the pNFS block layout extension. In this +case 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 to directly access the underlying block devices that is
s/is/are/.
+shared with the client. Note that there are no Data Servers (DSs) in the +block layout flavor of pNFS. + +To use pNFS block layouts with with the Linux NFS server the exported file +system needs to support the pNFS block layouts (current just XFS), and the +file system must sit on shared storage (typically iSCSI) that is accessible +to the clients as well as the server. The file system needs to either sit +directly on the exported volume, or on a RAID 0 using the MD software RAID +driver with the version 1 superblock format. If the filesystem uses sits +on a RAID 0 device the clients will automatically stripe their I/O over +multiple LUNs. + +On the server pNFS block volume support is automatically if the file system
s/automatically/automatically enabled/. So there's no server-side configuration required at all? --b.
+support its. On the client make sure the kernel has the CONFIG_PNFS_BLOCK +option enabled, the blkmapd daemon from nfs-utils is running, and the +file system, is mounted using the NFSv4.1 protocol version (mount -o vers=4.1). + +If the nfsd server needs to fence a non-responding client it calls +/sbin/nfsd-recall-failed with the first argument set to the IP address of +the client, and the second argument set to the device node without the /dev +prefix for the filesystem to be fenced. Below is an example file that show +how to translate the device into a serial number from SCSI EVPD 0x80:
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