Even with small timeo and retrans, you won't get i/o errors back to the reads/writes. That's been our experience anyway.
With soft, you may end up with lost data (data that had already been written to the cache but not yet to the storage). You'd have that same issue with 'hard' too if it was your appliance that failed. If the appliance never comes back, those blocks can never be written.
In your case though, you're not writing.
-----Original Message-----
From: Andrew Martin <amartin@xxxxxxxxxxx>
Date: Thu, 6 Mar 2014 10:43:42
To: Jim Rees<rees@xxxxxxxxx>
Cc: <bhawley@xxxxxxxxxxx>; NeilBrown<neilb@xxxxxxx>; <linux-nfs-owner@xxxxxxxxxxxxxxx>; <linux-nfs@xxxxxxxxxxxxxxx>
Subject: Re: Optimal NFS mount options to safely allow interrupts and
timeouts on newer kernels
> From: "Jim Rees" <rees@xxxxxxxxx>
> Andrew Martin wrote:
>
> > From: "Jim Rees" <rees@xxxxxxxxx>
> > Given this is apache, I think if I were doing this I'd use
> > ro,soft,intr,tcp
> > and not try to write anything to nfs.
> I was using tcp,bg,soft,intr when this problem occurred. I do not know if
> apache was attempting to do a write or a read, but it seems that
> tcp,soft,intr
> was not sufficient to prevent the problem.
>
> I had the impression from your original message that you were not using
> "soft" and were asking if it's safe to use it. Are you saying that even with
> the "soft" option the apache gets stuck forever?
Yes, even with soft, it gets stuck forever. I had been using tcp,bg,soft,intr
when the problem occurred (on several ocassions), so my original question was
if it would be safe to use a small timeo and retrans values to hopefully
return I/O errors quickly to the application, rather than blocking forever
(which causes the high load and inevitable reboot). It sounds like that isn't
safe, but perhaps there is another way to resolve this problem?
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