On Tue, Sep 23, 2008 at 12:41 PM, Talpey, Thomas <Thomas.Talpey@xxxxxxxxxx> wrote: > One other comment... > > At 12:16 PM 9/23/2008, Chuck Lever wrote: >>Document the interaction between the mountproto= and the proto= mount >>options in a new subsection of nfs(5). >> >>Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> >>--- >> >> utils/mount/nfs.man | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 files changed, 81 insertions(+), 0 deletions(-) >> >>diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man >>index b1037a8..48f2153 100644 >>--- a/utils/mount/nfs.man >>+++ b/utils/mount/nfs.man >>@@ -831,6 +831,87 @@ and >> .B wsize >> can safely be allowed to default to the largest values supported by >> both client and server, independent of the network's MTU size. >>+.SS "Interaction between the proto and mountproto options" >>+The Linux NFS client can use a different transport protocol for >>+contacting an NFS server's rpcbind service, its mountd service, >>+its NLM service, and its NFS service. >>+The exact transport protocols employed by the Linux NFS client for >>+each mount point depends on the settings of the transport protocol >>+mount options, which include >>+.BR proto , >>+.BR mountproto , >>+.BR udp ", and " tcp . >>+.P >>+The NSM protocol uses the UDP transport >>+no matter what transport specific options are specified. > > This actually isn't true - in fact the client NSM by default listens on > both UDP and TCP, as can be seen with rpcinfo -p. > > What is true is that the vast majority of NFS servers call back on UDP, > and if this fails, there is no indication at the client whatsoever. > > So the text should perhaps say "NFS servers typically choose UDP for the > NSM protocol; the client in any case accepts both UDP and TCP." Granted that this text should be tuned a bit, but... Even though rpc.statd listens on TCP as well, Linux sm-notify requests go out only on UDP; and there is no mount option to change any of this behavior. NSM is a bit of a challenge to describe because both ends act as a client and a server. -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
