From owner-freebsd-current@freebsd.org Tue Jun 19 00:37:35 2018 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id F08D2100959A; Tue, 19 Jun 2018 00:37:34 +0000 (UTC) (envelope-from truckman@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 95AFF7BFBB; Tue, 19 Jun 2018 00:37:34 +0000 (UTC) (envelope-from truckman@FreeBSD.org) Received: from mousie.catspoiler.org (unknown [76.212.85.177]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: truckman) by smtp.freebsd.org (Postfix) with ESMTPSA id EB81D17B16; Tue, 19 Jun 2018 00:37:33 +0000 (UTC) (envelope-from truckman@FreeBSD.org) Date: Mon, 18 Jun 2018 17:37:32 -0700 (PDT) From: Don Lewis Subject: Re: review of nfsd rc.d script patch To: Rick Macklem cc: "rc@freebsd.org" , "freebsd-current@freebsd.org" In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=us-ascii Content-Disposition: INLINE X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Jun 2018 00:37:35 -0000 On 15 Jun, Rick Macklem wrote: > Hi, > > For the pNFS service MDS machine, the nfsd can't be started until all nfs mounts > in /etc/fstab are done. > I think that adding "mountcritremote" to the "# REQUIRE:" line is sufficient to do this? > > I don't think delaying the startup of the nfsd daemon until after any NFS mounts > are done will do any harm, but if others think it would be a POLA violation, > I could make this dependent on the pNFS service being enabled. > Does anyone think this would cause a POLA violation? Sounds like that would break cross mounts. Back in the olden days before the automounter, I would set up workstation clusters with hosta exporting local filesystem /home/hosta, and hostb exporting /home/hostb. In addition, hosta would do a bg NFS mount of /home/hostb and hostb would do a bg NFS mount of /home/hosta. That way everybody would have a consistent view of everything. If a power failure took down everything, the first system up would export its local filesystem and even though it wouldn't be able to mount any remote filesystems, mount would background itself at the boot would complete. As the remaining machines came up, they would be able to mount the remote filesystems of the machine that came up earlier, and the early machines would mount the filesystems from the later machines as they became available. If nfsd is delayed until all the NFS filesystems are mounted, the above setup would deadlock.