Is this ready to go?? steved. 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. > +The NFSACL protocol shares the same RPC transport as the main NFS > +service. > +.P > +If no transport protocol options are specified, the Linux NFS client > +uses UDP to contact the server's mountd service, and TCP to > +contact its NLM and NFS services by default. > +.P > +UDP is a good choice for contacting the mountd server since most > +common NFS servers support UDP for mountd, UDP generates less network > +traffic, and UDP does not leave extra ports in TIME_WAIT after the > +mountd request is complete. > +However, a reliable stream transport such as TCP is a good choice for > +NFS and NLM because these must handle large requests and must be > +immune to network problems that might cause RPC requests to be lost. > +.P > +If the server does not support these transports for these services, the > +.BR mount (8) > +command attempts to discover what the server supports, and then retries > +the mount request once using the discovered transport protocols. > +If the server does not advertise any transport supported by the client > +or is misconfigured, the mount request fails. > +If the > +.B bg > +option is in effect, the mount command backgrounds itself and continues > +to attempt the specified mount request. > +.P > +When the > +.B proto > +option, the > +.B udp > +option, or the > +.B tcp > +option is specified but the > +.B mountproto > +option is not, the specified transport is used to contact > +both the server's mountd service and for the NLM and NFS services. > +.P > +If the > +.B mountproto > +option is specified but none of the > +.BR proto ", " udp " or " tcp > +options are specified, then the specified transport is used for the > +initial mountd request, but the mount command attempts to discover > +what the server supports for the NFS protocol, preferring TCP if > +both transports are supported. > +.P > +If both the > +.BR mountproto " and " proto > +(or > +.BR udp " or " tcp ) > +options are specified, then the transport specified by the > +.B mountproto > +option is used for the initial mountd request, and the transport > +specified by the > +.B proto > +option (or the > +.BR udp " or " tcp " options)" > +is used for NFS, no matter what order these options appear. > +No automatic service discovery is performed if these options are > +specified. > +.P > +If any of the > +.BR proto ", " udp ", " tcp ", " > +or > +.B mountproto > +options are specified more than once on the same mount command line, > +then the value of the rightmost instance of each of these options > +takes effect. > .SH "DATA AND METADATA COHERENCE" > Some modern cluster file systems provide > perfect cache coherence among their clients. > -- 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
