From: Olga Kornievskaia <aglo@umich.edu>
To: Benjamin Coddington <bcodding@redhat.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
linux-nfs <linux-nfs@vger.kernel.org>
Subject: Re: unsharing tcp connections from different NFS mounts
Date: Tue, 6 Oct 2020 17:46:11 -0400 [thread overview]
Message-ID: <CAN-5tyGDC0VQqjqUNzs_Ka+-G_1eCScVxuXvWsp7xe7QYj69Ww@mail.gmail.com> (raw)
In-Reply-To: <95542179-0C20-4A1F-A835-77E73AD70DB8@redhat.com>
On Tue, Oct 6, 2020 at 3:38 PM Benjamin Coddington <bcodding@redhat.com> wrote:
>
> On 6 Oct 2020, at 11:13, 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?
>
> I suppose you could just toggle the nfs4_unique_id parameter. This
> seems to
> work:
>
> flock /sys/module/nfs/parameters/nfs4_unique_id bash -c "OLD_ID=\$(cat
> /sys/module/nfs/parameters/nfs4_unique_id); echo imalittleteapot >
> /sys/module/nfs/parameters/nfs4_unique_id; mount -ov4,sec=sys
> 10.0.1.200:/exports /mnt/fedora2; echo \$OLD_ID >
> /sys/module/nfs/parameters/nfs4_unique_id"
>
> I'm trying to think of a reason why this is a bad idea, and not coming
> up
> with any. Can we support users that have already found this solution?
>
What about reboot recovery? How will each mount recover its own state
(and present the same identifier it used before). Client only keeps
track of one?
> Ben
>
next prev parent reply other threads:[~2020-10-06 21:46 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 15:13 unsharing tcp connections from different NFS mounts J. Bruce Fields
2020-10-06 15:20 ` Chuck Lever
2020-10-06 15:22 ` Bruce Fields
2020-10-06 17:07 ` Tom Talpey
2020-10-06 19:30 ` Bruce Fields
[not found] ` <CAGrwUG5_KeRVR8chcA8=3FSeii2+4c8FbuE=CSGAtYVYqV4kLg@mail.gmail.com>
2020-10-07 14:08 ` Tom Talpey
2020-10-06 19:36 ` Benjamin Coddington
2020-10-06 21:46 ` Olga Kornievskaia [this message]
2020-10-07 0:18 ` J. Bruce Fields
2020-10-07 11:27 ` Benjamin Coddington
2020-10-07 12:55 ` Benjamin Coddington
2020-10-07 13:45 ` Chuck Lever
2020-10-07 14:05 ` Bruce Fields
2020-10-07 14:15 ` Chuck Lever
2020-10-07 16:05 ` Bruce Fields
2020-10-07 16:44 ` Trond Myklebust
2020-10-07 17:15 ` Bruce Fields
2020-10-07 17:29 ` Trond Myklebust
2020-10-07 18:05 ` bfields
2020-10-07 19:11 ` Trond Myklebust
2020-10-07 20:29 ` bfields
2020-10-07 18:04 ` Benjamin Coddington
2020-10-07 18:19 ` Trond Myklebust
2020-10-07 16:50 ` Trond Myklebust
2021-01-19 22:22 ` bfields
2021-01-19 23:09 ` Trond Myklebust
2021-01-20 15:07 ` bfields
2021-05-03 20:09 ` bfields
2021-05-04 2:08 ` NeilBrown
2021-05-04 13:27 ` Tom Talpey
2021-05-04 14:27 ` Trond Myklebust
2021-05-04 16:51 ` bfields
2021-05-04 21:32 ` Daire Byrne
2021-05-04 21:48 ` Trond Myklebust
2021-05-05 12:53 ` Daire Byrne
2021-01-20 15:58 ` Chuck Lever
2020-10-07 13:56 ` Patrick Goetz
2020-10-07 16:28 ` Igor Ostrovsky
2020-10-07 16:30 ` Benjamin Coddington
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