#Only NFSv3 is enabled on the vserver, but a volume mounted as NFSv4, Could it cause issues?

1 messages · Page 1 of 1 (latest)

stiff geyser
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If somebody can please point out what issues it could cause, particularly on the performance and why?

The client here is REDHAT. We changed mounting option on the client to NFSv3, but the result seems incosistency on performance. So, not clear if the version used on the client is a problem or not.

granite shore
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First, look at the vserver (vserver nfs show). If it only allows v3 then the client can only mount v3. Then look at the export policy rules.
NFS=v3+v4.0+v4.1+v4.2
NFSV3 =v3
NFS4 = v4.0+v4.1+v4.2

Look at the client. If NOTHING is asked for, it will work backwards 4.2, 4.1, 4.0, 3 until it finds a version that works

stiff geyser
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To answer your questions:

  • Yes, the vserver only allows v3 and v3 only.
    Are you saying then that the client supposedly can only be allowed to mount as ver3? But the fact was that the client was able to use ver4 to mount. What problem it could cause if vserver allows v3, but the client uses v4?
  • In export policy rules, the protocol is "nfs".
    Was this the reason of why the client could use v4 to mount, as you pointed out? even though the vserver can only allow v3?

Thank you!

tulip quarry
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if the SVM has v4 disabled then you can only use NFS v3

stiff geyser
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Even export policy rules allow “nfs”(NFSv4)?

granite shore
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Yes. If the vserver specifically has v4.0 and v4.1 disabled it will be impossible to mount with anything except v3 even if the export policy rule says 4.0

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On the client side, run the “mount“ command and verify vers or nfsvers depending on platform

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There is an exception to this:
esxi and vaai. If you enable vstorage and v3 and disable v4.0/4.1 and set the export policy rule to protocol =nfs then the ESXi host will communicate “over back channels” that looks like v4 for the vaai to work

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It will still mount the data store using v3 but communicate the vaai directives via v4 (but not for nfs-data)

mortal zinc
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You can confirm via packet trace, but TMAC is correct as usual.

stiff geyser
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Yes, TMAC is very helpful here.
One more follow-up question: Likewise, if vserver only allows NFSv4, and NFSv4 only then, the client cannot mount the volume as NFSv3, correct?

granite shore
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That’s also correct

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You can only mount to the svm based on what protocols are enabled AND then if the export-policy rules allow

mortal zinc
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You might check the nfs conf file on the client to see what version it allows. It's in different locations depending on your distro of Linux.