[one-users] Shared-NFS - vm creation hangs when NFS connection is lost

[Rangababu Chakravarthula]

I take it back. send out that email after waiting for a while but now the
client came back with an ERROR and all the processes got cleaned up. But it
did take a while before failing.

Ranga

On Tue, May 3, 2011 at 4:40 PM, Rangababu Chakravarthula <rbabu at hexagrid.com
> wrote:

> Lars
>
> Thanks for the quick response. I tried to mount with soft option & without
> "retrans" option. Still its the same behaviour. The man page says without
> "retrans" option, it would try 3 times and fail. However, in my case it
> didn't.
>
> Also there is a note with regard to "soft" option
>
>
> *NB: A so-called "soft" timeout  can  cause  silent  data corruption  in
> certain  cases.  As  such,  use the soft option only when client
> responsiveness is more important
> than  data  integrity.  Using NFS over TCP or increasing the value of the
> retrans option may mitigate some of the risks of using the soft option*.
>
> Still trying to find a solution.
>
>
> Ranga
>
>
> On Tue, May 3, 2011 at 2:52 PM, Lars Kellogg-Stedman <
> lars at seas.harvard.edu> wrote:
>
>> > between all the hosts to allow live migration.  If for any reason NFS
>> > connection is lost and user tries to create a new VM the following
>> > opennebula commands hangs and sits there for over.
>>
>> What mount options are you using for the storage?  In theory if you
>> mount with '-o soft', processes blocked on access to the storage will
>> eventually get an error.  This is from the nfs(5) man page:
>>
>>  If the soft option is  specified,  then  the  NFS  client fails an
>>  NFS request after retrans retransmissions have been sent, causing the
>>  NFS client to return an error to the calling application.
>>
>> In the sort of situation you describe, there's not really any way for
>> OpenNebula to "check the storage connectivity", because any commands
>> that attempt to access the storage will get stuck in exactly the same
>> way.
>>
>> --
>> Lars Kellogg-Stedman <lars at seas.harvard.edu>
>> Senior Technologist
>> Harvard University SEAS
>> Academic and Research Computing (ARC)
>>
>
>
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