From owner-freebsd-questions@FreeBSD.ORG Fri Sep 24 16:03:09 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0696A106566B for ; Fri, 24 Sep 2010 16:03:09 +0000 (UTC) (envelope-from tg@gmplib.org) Received: from shell.gmplib.org (gmplib-02.nada.kth.se [130.237.222.242]) by mx1.freebsd.org (Postfix) with ESMTP id BE5318FC17 for ; Fri, 24 Sep 2010 16:03:08 +0000 (UTC) Received: by shell.gmplib.org (Postfix, from userid 1001) id 4BB2F1072; Fri, 24 Sep 2010 18:03:06 +0200 (CEST) To: freebsd-questions@freebsd.org From: Torbjorn Granlund Sender: tg@gmplib.org Date: Fri, 24 Sep 2010 18:03:06 +0200 Message-ID: <867hibxh6t.fsf@shell.gmplib.org> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Mount order for ZFS, jails, and nullfs X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Sep 2010 16:03:09 -0000 In jails, I'd like a local ZFS /, a read-only nullfs-mounted /usr, and a local /usr/local. (I'd also have read-only nullfs-mounted /bin, /lib, /libexec, but let's forget about that for now.) This way, I can upgrade the master /usr once, in one place, and have all jails inherit it. And my dear jail inmates can install anything in /usr/local (such as their favourite packages/ports). I.e., things should look like this: /myjail/ zfs /myjail/usr nullfs ro /myjail/usr/local zfs There is no problem to make this happen by issuing a handful of commands manually after boot, but I cannot seem to get it to work automatically, with existing boot mechanism. The problem is that the mount of /usr will be attempted before ZFS has mounted /myjail, the jail's root. ZFS maintains its own mount table. It is possible to disable the automated mounting in ZFS by specifying the pseudo mountpoint "legacy", and then--according to the FreeBSD manual--mount it with mount(8). Unfortunately, FreeBSD's mount seems unable to perform mounts of ZFS volumes. How can I achieve the result I want after a reboot? (The reply "use ezjail!" is not the right one. :-) It does not do what I want to do. I dislike its symlink forest, and that it creates just one ZFS filesystem for the entire jail.) --=20 Torbj=F6rn