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Subject: Re: unsharing tcp connections from different NFS mounts
To:     "J. Bruce Fields" <bfields@fieldses.org>, linux-nfs@vger.kernel.org
References: <20201006151335.GB28306@fieldses.org>
From:   Patrick Goetz <pgoetz@math.utexas.edu>
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On 10/6/20 10:13 AM, J. Bruce Fields wrote:
> NFSv4.1+ differs from earlier versions in that it always performs
> trunking discovery that results in mounts to the same server sharing a
> TCP connection.
> 
> It turns out this results in performance regressions for some users;
> apparently the workload on one mount interferes with performance of
> another mount, and they were previously able to work around the problem
> by using different server IP addresses for the different mounts.
> 
> Am I overlooking some hack that would reenable the previous behavior?
> Or would people be averse to an "-o noshareconn" option?
> 
> --b.
> 


I don't see how sharing a TCP connection can result in a performance 
regression (the performance degradation of *not* sharing a TCP 
connection is why HTTP 1.x is being replaced), or how using different IP 
addresses on the same interface resolves anything.  Does anyone have an 
explanation?