From: Trond Myklebust <trondmy@hammerspace.com>
To: "bfields@fieldses.org" <bfields@fieldses.org>
Cc: "fsorenso@redhat.com" <fsorenso@redhat.com>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"aglo@umich.edu" <aglo@umich.edu>,
"bcodding@redhat.com" <bcodding@redhat.com>,
"jshivers@redhat.com" <jshivers@redhat.com>,
"chuck.lever@oracle.com" <chuck.lever@oracle.com>
Subject: Re: unsharing tcp connections from different NFS mounts
Date: Tue, 19 Jan 2021 23:09:55 +0000 [thread overview]
Message-ID: <2d77534fb8be557c6883c8c386ebf4175f64454a.camel@hammerspace.com> (raw)
In-Reply-To: <20210119222229.GA29488@fieldses.org>
On Tue, 2021-01-19 at 17:22 -0500, bfields@fieldses.org wrote:
> On Wed, Oct 07, 2020 at 04:50:26PM +0000, Trond Myklebust wrote:
> > As far as I can tell, this thread started with a complaint that
> > performance suffers when we don't allow setups that hack the client
> > by
> > pretending that a multi-homed server is actually multiple different
> > servers.
> >
> > AFAICS Tom Talpey's question is the relevant one. Why is there a
> > performance regression being seen by these setups when they share
> > the
> > same connection? Is it really the connection, or is it the fact
> > that
> > they all share the same fixed-slot session?
> >
> > I did see Igor's claim that there is a QoS issue (which afaics
> > would
> > also affect NFSv3), but why do I care about QoS as a per-mountpoint
> > feature?
>
> Sorry for being slow to get back to this.
>
> Some more details:
>
> Say an NFS server exports /data1 and /data2.
>
> A client mounts both. Process 'large' starts creating 10G+ files in
> /data1, queuing up a lot of nfs WRITE rpc_tasks.
>
> Process 'small' creates a lot of small files in /data2, which
> requires a
> lot of synchronous rpc_tasks, each of which wait in line with the
> large
> WRITE tasks.
>
> The 'small' process makes painfully slow progress.
>
> The customer previously made things work for them by mounting two
> different server IP addresses, so the "small" and "large" processes
> effectively end up with their own queues.
>
> Frank Sorenson has a test showing the difference; see
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1703850#c42
> https://bugzilla.redhat.com/show_bug.cgi?id=1703850#c43
>
> In that test, the "small" process creates files at a rate thousands
> of
> times slower when the "large" process is also running.
>
> Any suggestions?
>
I don't see how this answers my questions above?
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2021-01-19 23:11 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
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 [this message]
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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