On Mon, 2009-10-26 at 10:34 -0400, Steve Dickson wrote: > [With the next nfs-utils rawhide build, I will be flipping the ] > [switch that will cause all NFS client mounts to try NFS v4 first ] > [At the bottom of this email has the workarounds if this change does ] > [indeed cause pain ] > > As part of the https://fedoraproject.org/wiki/Features/NFSv4Default feature > I am one commit away from changing the default protocol version NFS will > be using (or at least trying to use). > > What does this means to you? Hopefully nothing! In theory this should > be a very seamless transition but with all new technology there > will be (and are) some rough spots. > > Why are make the change? See the NFSv4Default wiki for details, > but in a nutshell: > * Better performance - V4 is now a stateful protocol. Meaning the server keeps > state on all the clients access a particular file or directory. This > allows the server to give out delegations (or leases) which in turn > allows the client to aggressive cache both data and meta data locally > > * Firewall Friendly- With v4 only one port is used 2049 for all traffic > including mounting and file locking. > > * Finally it enables us use upcoming minor releases of the the protocol. > NFS version 4.1 and pNFS are two example of upcoming minor releases. > > > FYI, V4 was introduced in Fedora Core 2 so it has been around for a while. I > personally have been using it for my home directory for a couple years now.. > For more of the nitty gritty details see > http://www.iaps.com/NFSv4-new-features.html > > That's the good news... Here is the bad.... > > Because the mount command will try NFS v4 first, mounts to older Linux servers > will start failing like: > > # mount linux-server:/export /mnt > mount.nfs: mounting linux-server:/export failed, reason given by server: > No such file or directory > > This is due to a defect in the Linux server exporting code, which is fixed > in F-12, *but* there are a number of workarounds > > On the server (Which is suggested): > * Add the following entry to the /etc/exports file: > / *(ro,fsid=0) Note: 'fsid=0' is explained in the exports(5) man pages. > > On the client, go back to v3 mounts by doing one of the following: > > * Add -o v3 to command line, similar to: > mount linux-server:/export /mnt > > * Change the default mount version in the new /etc/nfsmount.conf file by > uncommenting the Nfsvers=3 setting in the 'NFSMount_Global_Options' section. > See nfsmount.conf(5) man page for details. The diff would look like: > > --- /etc/nfsmount.conf.orig 2009-10-26 09:30:21.000000000 -0400 > +++ /etc/nfsmount.conf 2009-10-26 10:31:30.227443686 -0400 > @@ -31,7 +31,7 @@ > # Protocol Version [2,3,4] > # This defines the default protocol version which will > # be used to start the negotiation with the server. > -# Defaultvers=4 > +Defaultvers=3 > # > # Setting this option makes it mandatory the server supports the > # given version. The mount will fail if the given version is Haven't gone through the full thread yet, but is it worth adding a note/admonition to our NFS installation instructions that changing the nfs server configuration may be necessary? http://docs.fedoraproject.org/install-guide/f12/en-US/html/ch03s05s02.html Thanks, James
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