On Thu, Apr 9, 2015 at 9:15 AM, Tom Horsley <horsley1953(a)gmail.com> wrote:
I've got a system running centos 7 hosting lots of filesystems
available for NFS mounting.
I've got a gazillion virtual machines that need to have their
fstab edited to mount these filesystems.
I've now discovered that mechanically editing the fstab doesn't
work. On most of the VMs, if I say something like this:
bob:/builder /bob/builder nfs rw,bg,hard,rsize=8192,wsize=8192 0 0
then everything "just works", but as I go back in time, when I get
to a machine running fedora 11, I get the highly informative
"incorrect mount option" message. With lots of experimentation,
I eventually found that I could change the type from "nfs" to "nfs4"
and the mount would work.
Is there a guide somewhere for which idioms to use for which version
of linux I want to mount in? Is there any way to automate adding
these fstab entries correctly? I thought the nfs server was supposed
to automatically fall back to old protocols if the client didn't know
something, am I missing some sort of configuration on the centos 7 host?
Fedora defaulted to nfsv4 with F13 so "mount -t nfs ..." on F11 would
default to nfsv3 and you had to use "mount -t nfs4 ..." to mount an
nfsv4 share.
"nfs4" is now deprecated (see "man nfs" on F13 or higher; or perhaps
F14 or higher).
Use "mount -t nfs -o nfsvers=<vers> ..." to specify a version, whether
2/3/4, except pre-F13 or pre-F14 (I can't remember which).
Before the "nfs4" option was deprecated, you specified an nfsv2 or
nfsv3 mount with "mount -t nfs -o nfsvers=<vers> ...", an nfsv4 mount
with "mount -t nfs4 ...", and you couldn't use "mount -t nfs -o
nfsvers=4 ..." for an nfsv4 mount.
You could use "nfs4" for all of your mounts from F11 to F21, until
it's removed, if ever.
You can check which nfs versions are being used by an nfs server with
"cat /proc/fs/nfsd/versions" or "rpcinfo -s" or "rpcinfo
-p".
CentOS 7 defaults to nfsv4 but unless you've disabled nfsv3 or are
running a firewall and haven't set nfs up to share through it, nfsv3
mounts should work. Try "mount -v -t nfs ..." on your F11 box and you
might get a more verbose error message (if you're lucky!).