From: "J. Bruce Fields" <bfields@fieldses.org>
To: DENIEL Philippe <philippe.deniel@cea.fr>
Cc: Thomas Haynes <thomas@netapp.com>, linux-nfs@vger.kernel.org
Subject: Re: Side effects of having NFSv4 mounted over udp
Date: Tue, 14 Dec 2010 14:15:14 -0500 [thread overview]
Message-ID: <20101214191514.GC24828@fieldses.org> (raw)
In-Reply-To: <4D071E32.905@cea.fr>
On Tue, Dec 14, 2010 at 08:35:14AM +0100, DENIEL Philippe wrote:
> Hi
> >The Linux server allows it, but I've been considering that a
> >(low-priority) bug, so it wouldn't be safe to assume it will continue
> >working.
> I am mostly thinking at the client side using as well udp and tcp.
> Would the "NFSv4 client over UDP" behaves differently then the same
> client over TCP ?
>
> >That aside, if you have a perfect network,
> I can trust my network. It's not a WAN, it's located into a very
> massive cluster (it's kind of "internal LAN"). It's a very high
> throughput network (IB based) so I believe there are less "hardware
> based reason" to loose packets.
>
> >NFSv4.0 at least will
> >probably work.
> OK.
> >(Not 4.1 since backchannel setup will fail?)
> What is erroneous in using UDP for NFSv4.1 backchannels ?
I assumed it would require some stronger notion of a "connection" than
UDP could provide. But maybe it could be made to work somehow.
> >Are you really sure that you can't make tcp scale to thousands of
> >clients?
> I am a bit afraid of a "No more file descriptors" effect. If I have
> one TCP socket per client and thousands of clients, I have less
> remaining fds for other purposes. Another point : UDP is a "cheap"
> protocol. I can have bunches of clients without overloading the
> server (a new client will almost cost nothing to the server, just
> the cost of a new clientid negotiation) .
Is the tcp state all that much more?
> I was wondering if it
> could be reliable to use it for NFSv4 inside a large cluster.
Well, it'd require some spec changes in any case.
--b.
prev parent reply other threads:[~2010-12-14 19:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-13 7:46 Side effects of having NFSv4 mounted over udp DENIEL Philippe
2010-12-13 19:04 ` Thomas Haynes
2010-12-13 19:16 ` J. Bruce Fields
2010-12-13 19:47 ` Trond Myklebust
2010-12-14 7:35 ` DENIEL Philippe
2010-12-14 19:15 ` J. Bruce Fields [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101214191514.GC24828@fieldses.org \
--to=bfields@fieldses.org \
--cc=linux-nfs@vger.kernel.org \
--cc=philippe.deniel@cea.fr \
--cc=thomas@netapp.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).