Date: Sat, 27 Feb 2010 14:03:10 -0800 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: rwatson@freebsd.org Cc: freebsd-fs@freebsd.org, stable@freebsd.org, Willem Jan Withagen <wjw@digiware.nl>, Eirik =?iso-8859-1?Q?=D8verby?= <ltning@anduin.net> Subject: Re: mbuf leakage with nfs/zfs? Message-ID: <20100227220310.GA65110@icarus.home.lan> In-Reply-To: <4B89943C.70704@digiware.nl> References: <20100226174021.8feadad9.gerrit@pmp.uni-hannover.de> <E1Nl6VA-000557-D9@kabab.cs.huji.ac.il> <20100226224320.8c4259bf.gerrit@pmp.uni-hannover.de> <4B884757.9040001@digiware.nl> <20100227080220.ac6a2e4d.gerrit@pmp.uni-hannover.de> <4B892918.4080701@digiware.nl> <20100227202105.f31cbef7.gerrit@pmp.uni-hannover.de> <20100227193819.GA60576@icarus.home.lan> <BD8AC9F6-DF96-41F9-8E92-48A4E5606DC7@anduin.net> <4B89943C.70704@digiware.nl>
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On Sat, Feb 27, 2010 at 10:53:00PM +0100, Willem Jan Withagen wrote: > On 27-2-2010 21:32, Eirik Øverby wrote: > >I've had a discussion with some folks on this for a while. I can easily > >reproduce this situation by mounting a FreeBSD ZFS filesystem via > >NFS-UDP from an OpenBSD machine. Telling the OpenBSD machine to use TCP > >instead of UDP makes the problem go away. > > > >Other FreeBSD systems mounting the same share, either using UDP or TCP, > >does not cause the problem to show up. > > > >A patch was suggested by Rick Macklem, but that did not solve the issue: > >http://lists.freebsd.org/pipermail/freebsd-current/2009-December/014181.html > > I concur. > Everything in my network is now on TCP, and there is no mbuf leakage. > I just don't get over the 5500 mark, no matter what I throw at it. > > I do feel that TCP is not as well performing on a local net with Linux, > hence the choice for UDP. But TCP is workable as next best. I'm pulling in Robert Watson, who has some familiarity with the UDP stack/code in FreeBSD. I'm not sure he'll be a sufficient source of knowledge for this specific issue since it appears (?) to be specific to NFS; Rick Macklem would be a better choice, but as reported, he's MIA. Robert, are you aware of any changes or implementation issues which might cause excessive (read: leaking) mbuf use under UDP-based NFS? Do you know of a way folks could determine the source of the leak, either via DDB or while the system is live? -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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