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

[Rangababu Chakravarthula]

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)
>



-- 

*Rangababu Chakravarthula
VP Product Development
Hexagrid Computing, Inc.

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