Re: NFSv4 console messages (locks lost etc.)

Hi,

I should have mentioned that the server is FreeBSD -STABLE running newnfs, and the network isn't partitioned (because I access the box over SSH at the same time I see these messages.)

They only appear under heavy NFS load (portmaster build of math/R in this case.)

Lars

On Jun 29, 2013, at 2:32, Rick Macklem <rmacklem_at_uoguelph.ca> wrote:

> Lars Eggert wrote:
>> Hi,
>> 
>> on a -CURRENT client, I get quite a number of console messages under
>> heavy NFSv4 load, such as:
>> 
>> nfsv4 expired locks lost
> Means the lease expired on the NFSv4 server somehow. Lease
> expiry is "bad news" and there is no way to recover locks
> lost because of it.
>> nfscl: never fnd open
> Usually, opens can be recovered after a lease expiry, but it
> might be broken. Since lease expiry should never happen during
> normal operation (see below), it doesn't get a lot of testing.
> 
>> nfscl: never fnd open
>> nfscl: never fnd open
>> nfsv4 expired locks lost
>> nfscl: never fnd open
>> nfscl: never fnd open
>> nfsv4 expired locks lost
>> nfsv4 expired locks lost
>> nfsv4 expired locks lost
>> nfsv4 expired locks lost
>> nfsv4 expired locks lost
>> nfscl: never fnd open
>> 
>> Can I ignore them? Can I turn them off?
>> 
> Well, these should never happen during normal, correct operation. The
> "nfsv4 expired locks lost" implies lease expiry. This should only happen
> when the client is network partitioned from the server for more than
> a lease duration (chosen by the server, but typically about 1minute).
> The client does a Renew Op every 1/2 lease durations to avoid this. Also,
> any state related operation (open/lock/locku/close/etc) is supposed to
> renew the lease implicitly.
> 
> If you are getting network partitions happening, then you really need
> to fix the network.
> 
> If not, then if you watch network traffic with something like wireshark
> and see Renew Ops happening at regular intervals, then I can only suggest
> that the server is somehow broken for NFSv4. You should also look for
> NFS4ERR_EXPIRED error replies to operations related to state (open/lock/locku/close).
> That is the server reply which indicates the lease expiry. If the server is
> never returning this, I have no idea how the client would generate the above
> messages, but it does indicate a client NFSv4 bug if that is the case.
> 
> Switching all mounts to NFSv3 will get rid of the above, although it is
> not exactly a fix;-)
> 
> rick
> 
>> Thanks,
>> Lars
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