From owner-freebsd-stable@FreeBSD.ORG Fri Jul 4 21:20:55 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 51C1A7E0 for ; Fri, 4 Jul 2014 21:20:55 +0000 (UTC) Received: from esa-jnhn.mail.uoguelph.ca (esa-jnhn.mail.uoguelph.ca [131.104.91.44]) by mx1.freebsd.org (Postfix) with ESMTP id 17F962394 for ; Fri, 4 Jul 2014 21:20:54 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqYEAKMZt1ODaFve/2dsb2JhbABSCBaDSlqCb7t9hmxTAYEhdYQDAQEBBAEBASArIAsbGAICDRkCKQEJJg4HBAEaAgSIIQ2vRJsTF4EsgTWLawUBARsBMwcWgmGBTAWYCoQ0jDOGEYNfITWBBTk X-IronPort-AV: E=Sophos;i="5.01,603,1400040000"; d="scan'208";a="137654181" Received: from muskoka.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.222]) by esa-jnhn.mail.uoguelph.ca with ESMTP; 04 Jul 2014 17:20:47 -0400 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id DB36DB3F48; Fri, 4 Jul 2014 17:20:47 -0400 (EDT) Date: Fri, 4 Jul 2014 17:20:47 -0400 (EDT) From: Rick Macklem To: kpneal@pobox.com Message-ID: <1127183499.7467557.1404508847886.JavaMail.root@uoguelph.ca> In-Reply-To: <20140704175251.GB62030@neutralgood.org> Subject: Re: FreeBSD 10.x + LiquidSoap + NFS == Server Hang MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [172.17.91.209] X-Mailer: Zimbra 7.2.6_GA_2926 (ZimbraWebClient - FF3.0 (Win)/7.2.6_GA_2926) Cc: Marc Fournier , freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Jul 2014 21:20:55 -0000 Kevin P. Neal wrote: > On Fri, Jul 04, 2014 at 09:33:48AM -0700, Marc Fournier wrote: > > I=E2=80=99ve made the change on two of my servers that have been exhibi= ting > > NFS related issues, so we=E2=80=99ll see how this goes over the next > > couple of days, but am curious as to when one would use =E2=80=98intr= =E2=80=99 in > > the first place, if by using it, it could cause NFS to hang like > > this? Granted, out of 11 servers using =E2=80=98intr=E2=80=99, this on= e server is > > the only one that I=E2=80=99ve knowingly experienced the nfs_getpages, = so > > it seems to be something hard to trigger =E2=80=A6 >=20 > It used to be that if you had an nfs mount that was nointr, and the > server > died, then any client programs that were in the middle of an I/O > would > hang forever. Well, until the server comes back up, actually. There is no perfect solution, but I always used hard mounts (no intr, soft) and just tried to make sure my NFS servers were reliable (same w.r.t. netwo= rk fabric), when I wore a sysadmin hat. There is "umount -f", which can get rid of a hung server. Unfortunately, if you do a "umount" (without -f) that is stuck on the crashed server's mount point, "umount -f" won't work, because the other "umount" will have the mou= nt point locked up. rick ps: Both John Baldwin and Kostik have made changes to how certain signals a= re handled during syscalls (and also what happens when an nfs_getpages() f= ails) so the behaviour is dependent upon FreeBSD version. > -- > Kevin P. Neal > http://www.pobox.com/~kpn/ > "Oh, I've heard that paradox a couple of times, but there's something > about a cat dying and I hate to think of such things." > - Dr. Donald Knuth speaking of Schrodinger's cat, December 8, 1999, > MIT > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to > "freebsd-stable-unsubscribe@freebsd.org"