From: Rick Macklem <rmacklem@uoguelph.ca>
To: Olga Kornievskaia <aglo@umich.edu>,
        "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
CC: linux-nfs <linux-nfs@vger.kernel.org>
Subject: Re: question: re-try of operations in PNFS
Date: Wed, 23 May 2018 00:26:20 +0000
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Olga Kornievskaia wrote:
[good stuff snipped]
>Upstream kernel. But I'm arguing that there shouldn't be a need to
>specify a dataserver_timeo because it shouldn't timeout at all just
>like MDS operations.
If/when the server is providing mirrored DSs, I've found this timeout useful
in the FreeBSD client since it allows the client to detect a DS failure.
It can then report the failure to the MDS via LayoutReturn (or another one
on NFSv4.2 which I can't remember the name of since I haven't done 4.2;-).

For non-mirrored DSs, the only thing I can think of (I've never seen this) would
be some sort of network partitioning such that the client can't reach the DS but
can reach the MDS.

I have no idea if this is relevant to Linux, but thought I'd mention it, just in case.
[more stuff snipped]
rick