From owner-freebsd-net@FreeBSD.ORG Wed Dec 17 03:45:57 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 440DDE74 for ; Wed, 17 Dec 2014 03:45:57 +0000 (UTC) Received: from acipenser.esturion.net (acipenser.esturion.net [65.101.5.252]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 17927FC6 for ; Wed, 17 Dec 2014 03:45:56 +0000 (UTC) Received: by acipenser.esturion.net (Postfix, from userid 112) id 3DC93260347; Tue, 16 Dec 2014 20:40:00 -0700 (MST) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on acipenser.esturion.net X-Spam-Level: X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham autolearn_force=no version=3.4.0 Received: from feyerabend.n1.pinyon.org (quine.pinyon.org [65.101.5.249]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by acipenser.esturion.net (Postfix) with ESMTPSA id 1BE12260133 for ; Tue, 16 Dec 2014 20:39:55 -0700 (MST) Message-ID: <5490FB0A.9060702@pinyon.org> Date: Tue, 16 Dec 2014 20:39:54 -0700 From: "Russell L. Carter" User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: freebsd-net@freebsd.org Subject: Re: compiling on nfs directories References: <2048229686.13136235.1418677169130.JavaMail.root@uoguelph.ca> <201412161337.58789.jhb@freebsd.org> In-Reply-To: <201412161337.58789.jhb@freebsd.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Dec 2014 03:45:57 -0000 On 12/16/14 11:37, John Baldwin wrote: > On Monday, December 15, 2014 3:59:29 pm Rick Macklem wrote: [...] >> What I suspect might cause this is one of two things: >> 1 - The modify time of the file is now changing at a time the Linux >> client doesn't expect, due to changes in ZFS or maybe TOD clock >> resolution. (At one time, the TOD clock was only at a resolution >> of 1sec, so the client wouldn't see the modify time change often. >> I think it is now at a much higher resolution, but would have to >> look at the code/test to be sure.) > > No, it's still only a second resolution on FreeBSD by default. You can > make this precise on the NFS server by setting the vfs.timestamp_precision > sysctl to 3. We should probably be using that by default for at least > server-class systems. > Hmm, what's this? Let's see: rcarter@feyerabend> uname -a FreeBSD feyerabend.n1.pinyon.org 10.1-STABLE FreeBSD 10.1-STABLE #1 r275516+3a52b5f(stable-jhb-em): Sat Dec 6 10:37:16 MST 2014 toor@feyerabend.n1.pinyon.org:/usr/obj/usr/src/sys/RLCGSV amd64 rcarter@feyerabend> man -k vfs.timestamp_precision vfs.timestamp_precision: nothing appropriate rcarter@feyerabend> sysctl -d vfs.timestamp_precision vfs.timestamp_precision: File timestamp precision (0: seconds, 1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to ms, 3+: sec + ns (max. precision)) rcarter@feyerabend> sysctl vfs.timestamp_precision vfs.timestamp_precision: 0 Ah, that's *VERY* interesting. I am unfortunately leaving the physical vicinity of my server farm soon, so not the right time for experiments. But I have been whining for some time now about what looks to be very similar to gerrit.kuehn's symptoms. I see them on installworlds via NFS v4.1, on -current or stable/10-trunk. About 9 out of 10 installs fail trying to rebuild parts of the tree. I finally resorted to copying /usr/obj* around and then just mounting /usr/src via NFS. ick. Oh, and also buildworld/buildkernel -j1. A pity on a cluster where 8 cores/system are the norm. But now I have something sensible to try. Looking forward to it. Happy holidays, and cheers! Russell