[rhelv6-list] NFS ID map?

[Chris Adams]

Once upon a time, Bryan J Smith <b.j.smith at ieee.org> said:
> Both RHEL5 and RHEL6 work fine with NFS4.  Although RHEL4 is capable
> of supporting NFS4, I don't recommend it.
> 
> So ... are you sure you're actually getting NFS4 on RHEL6?  Check with
> /proc/mounts to be sure.  ;)
> 
> Long story short ... file system type "nfs" during mount differs on
> RHEL6 from RHEL5.  You use "nfs" with option "vers=4" and not just
> type "nfs4" on RHEL6.  In fact, although don't quote me, but I think
> nfs4 = nfs on RHEL6, with the "vers=" being everything.

Yep, I did check /proc/mounts to make sure.  I can mount /srv/foo with
nfsvers=3 and /foo with nfsvers=4 on RHEL 6 (-t nfs4 also does still get
nfsvers=4 on RHEL 6; I think that's gone away with newer Fedoras, so
probably will in RHEL 7).

> Another reason I say this ... NFS4 exports work completely _different_
> than NFSv3.  You _must_ use fsid=0 and mount on the server under that
> tree.  That's completely different than NFSv3.  One can use bind
> mounts to solve such, but it also offers the nice feature of no longer
> having to export everything.

Yes, I have /srv with fsid=0.  The RHEL 6 clients can definately mount
with both NFSv3 and NFSv4 (checking /proc/mounts after mounting), but
the RHEL 5 clients are only working with NFSv3 (when I need NFSv4 for
the ID map).

Oh, I figured out my problem - this temporary/migration export is on a
different subnet, and my fsid=0 export was was only for the new subnet.
D'oh!  Fixed that, and NFSv4, and ID mapping (with the default config),
are now working.  Now, on with the (migration) show!

Thanks!
-- 
Chris Adams <linux at cmadams.net>