Re: boot-time nfs mount issues should be fixed now

[David Rhodus <drhodus@xxxxxxxxxxx>]

On Apr 13, 2004, at 6:03 PM, Matthew Dillon wrote:

>     The symptoms are NFS mount failures reported on the console, but 
> the
>     NFS mount working just fine when executed manually after booting as
>     completed.
>
>     It turns out that the DNS resolver coupled with the use of 
> short-form
>     names in /etc/fstab was to blame for this.    e.g. leaf has this:
>
> crater:/usr/src /usr/src        nfs     ro,bg           0       0
> apollo:/FreeBSD /FreeBSD        nfs     ro,bg           0       0
>
>     And sometimes /FreeBSD would not mount during booting.  It turns 
> out
>     that the network is sometimes not fully operational when the RCNG
>     script gets to the NFS mounts and this causes the DNS resolver to 
> fail.
>
>     Normally one would expect the resolver to retry a few times and 
> obtain
>     a successful lookup.  However, when a shortform name like 'crater' 
> is
>     used the resolver winds up trying two hostnames 
> 'crater.dragonflybsd.org.'
>     and 'crater.'.  If the first lookup times out, but the second one 
> does
>     not, the resolver returns the 'definitive' host-not-found error 
> from
>     the second lookup when it really should return a try-again error 
> from
>     the first lookup.  The result is that the NFS mount fails because 
> it
>     thinks that it was given definitely a non-existant hostname.
>
>     This problem can also cause weird failures to occur when the 
> network
>     is sporatic or the name servers you are using get overloaded.
>
>     In anycase, I just committed a fix to the resolver (which hopefully
>     won't break anything else).


Thanks, thats been a pain for a very long time.

-DR