NFS Locking Problem with Fully Qualified Hostnames - NFS

This is a discussion on NFS Locking Problem with Fully Qualified Hostnames - NFS ; Dear All, I'm not a unix administrator (he's off sick!) and I'm out of my depth so I'd appreciate any help anyone could offer on the following problem. We have an NFS set-up :- both servers and clients are running ...

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Thread: NFS Locking Problem with Fully Qualified Hostnames

  1. NFS Locking Problem with Fully Qualified Hostnames

    Dear All,

    I'm not a unix administrator (he's off sick!) and I'm out of my depth
    so I'd appreciate any help anyone could offer on the following problem.

    We have an NFS set-up :- both servers and clients are running Solaris
    9. "Casual" use of the NFS mount looks ok - we can create/edit/delete
    files etc. However we have a 3rd party application which will hang
    when writing to the NFS mount. I've traced the system call and it
    looks like this:

    fcntl(259, F_SETLK, 0xFFFFFFFF7FFF8FC8) (sleeping...)

    It sleeps forever (or until it is killed).

    Oddly, I've noticed that if I add a new entry in /etc/hosts on the
    server which included the UNqualified hostnames of the clients, and
    then re-export the filesystems, this seems to work ok. However, the
    normal situation - fully qualified names resolved by DNS - doesn't work
    for this particular system call. We can probably live with this
    workaround but it seems a bit "hacky" and was wondering if anyone could
    explain what was going on.

    Many thanks
    Charlotte


  2. Re: NFS Locking Problem with Fully Qualified Hostnames

    charlottejanehammond@yahoo.com wrote:
    > Dear All,
    >
    > I'm not a unix administrator (he's off sick!) and I'm out of my depth
    > so I'd appreciate any help anyone could offer on the following problem.
    >
    > We have an NFS set-up :- both servers and clients are running Solaris
    > 9. "Casual" use of the NFS mount looks ok - we can create/edit/delete
    > files etc. However we have a 3rd party application which will hang
    > when writing to the NFS mount. I've traced the system call and it
    > looks like this:
    >
    > fcntl(259, F_SETLK, 0xFFFFFFFF7FFF8FC8) (sleeping...)
    >
    > It sleeps forever (or until it is killed).
    >
    > Oddly, I've noticed that if I add a new entry in /etc/hosts on the
    > server which included the UNqualified hostnames of the clients, and
    > then re-export the filesystems, this seems to work ok. However, the
    > normal situation - fully qualified names resolved by DNS - doesn't work
    > for this particular system call. We can probably live with this
    > workaround but it seems a bit "hacky" and was wondering if anyone could
    > explain what was going on.
    >
    > Many thanks
    > Charlotte
    >


    Check that you get identical response on the server and the clients:

    getent hosts
    getent hosts

    Otherwise correct the hosts entry in /etc/nsswitch.conf,
    or the related name service.

    --
    Michael Tosch @ hp : com

  3. Re: NFS Locking Problem with Fully Qualified Hostnames

    Thank you very much Michael and Andrew!

    The problem appears to be the /etc/hosts file on the clients which
    containted the _unqualified_ hostname, which contrasted with the server
    which used DNS only to resolved the _qualified_ hostname. I don't
    understand why this problem only manifests for this single application
    while everything else appeared to work ok on the NFS mount. However,
    removing the local /etc/hosts entry so that the client also used DNS
    seems to have cleared the problem, so I'm happy.

    Many thanks again
    Charlotte
    Andrew Gabriel wrote:
    > In article ,
    > Michael Tosch writes:
    > >
    > > Check that you get identical response on the server and the clients:
    > >
    > > getent hosts
    > > getent hosts

    >
    > Check ipnodes before hosts (which is what the software does),
    > unless you commented ipnodes out in /etc/nsswitch.conf.
    >
    > > Otherwise correct the hosts entry in /etc/nsswitch.conf,
    > > or the related name service.

    >
    > --
    > Andrew Gabriel



  4. Re: NFS Locking Problem with Fully Qualified Hostnames

    Charlotte Hammond wrote:
    > Thank you very much Michael and Andrew!
    >
    > The problem appears to be the /etc/hosts file on the clients which
    > containted the _unqualified_ hostname, which contrasted with the server
    > which used DNS only to resolved the _qualified_ hostname. I don't
    > understand why this problem only manifests for this single application
    > while everything else appeared to work ok on the NFS mount. However,
    > removing the local /etc/hosts entry so that the client also used DNS
    > seems to have cleared the problem, so I'm happy.
    >


    Only locking seems affected. Few applications do locking.

    I suspect a bug somewhere in the statd/lockd code,
    maybe since a change in the system's name resolution.


    --
    Michael Tosch @ hp : com

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