NFS mount error
Geoffrey Leach
geoff at hughes.net
Sun Jan 24 00:44:03 UTC 2010
On 01/23/2010 02:39:44 PM, Sam Sharpe wrote:
> On 23 January 2010 22:17, Craig White <craigwhite at azapple.com> wrote:
> > On Sat, 2010-01-23 at 13:59 -0800, Geoffrey Leach wrote:
> >> I've got a simple network, systems 'A' and 'B' connected via
> wireless.
> >> B wants to mount A's /, /home and /usr/local. The fstab entries
> are
> >> A:/ /A nfs defaults 0 0
> >> A:/home /A-home nfs defaults 0 0
> >> A:/usr/local /A-ul nfs defaults 0 0
> >>
> >> With this, B should do the mounts at boot time, assuming A is on
> line,
> >> which it is.
> >>
> >> The curious thing is that the mount of A:/ works fine. mounts of
> A:/
> >> home and A:/usr/local fail with "mount.nfs: Unknown error 521"
> >>
> >> FWIW, B is running Fedora 10, while A is running up-to-date Fedora
> 12.
> >> This worked find prior to reloading F12 on A. Presumably I've
> missed
> >> something -- any ideas?
> > ----
> > at the point of having A:/ already mounted, the other mounts are
> > redundant and confusing.
>
> Actually they are not - the directories /A/home and /A/usr/local will
> be blank by default, because they will not be exported with the
> "nohide" option in /etc/exports. Mounting them separately might be
> what the OP perceives is the solution to this.
>
> nohide
> This option is based on the option of the same name
> provided in
> IRIX NFS. Normally, if a server exports two
> filesystems
> one of
> which is mounted on the other, then the client
> will
> have to
> mount both filesystems explicitly to get access to
> them.
> If it
> just mounts the parent, it will see an empty
> directory at the
> place where the other filesystem is mounted. That
> filesystem is
> "hidden".
>
> Setting the nohide option on a filesystem causes it
> not to be
> hidden, and an appropriately authorised client will be
> able to
> move from the parent to that filesystem without
> noticing the
> change.
>
> However, some NFS clients do not cope well with this
> situation
> as, for instance, it is then possible for two files
> in
> the one
> apparent filesystem to have the same inode number.
>
> The nohide option is currently only effective on
> single host
> exports. It does not work reliably with netgroup,
> subnet, or
> wildcard exports.
>
> The other interesting option in /etc/exports that may be worth
> experimenting with is "crossmnt":
>
> crossmnt
> This option is similar to nohide but it makes it
> possible for
> clients to move from the filesystem marked with
> crossmnt to
> exported filesystems mounted on it. Thus when a child
> filesys-
> tem "B" is mounted on a parent "A", setting crossmnt
> on
> "A" has
> the same effect as setting "nohide" on B.
>
Sam,
Thanks for the suggestion. I'll report how well they work out.
Regarding Craig's comment, /home and /usr/local are in seperate
partitions, so access via / is not possible.
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