From owner-freebsd-questions@FreeBSD.ORG  Sun Feb 15 03:53:52 2015
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 8A05AC15
 for <freebsd-questions@freebsd.org>; Sun, 15 Feb 2015 03:53:52 +0000 (UTC)
Received: from glockenspiel.complete.org (glockenspiel.complete.org
 [192.99.4.47])
 (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 63AF6E9
 for <freebsd-questions@freebsd.org>; Sun, 15 Feb 2015 03:53:51 +0000 (UTC)
Received: from [63.245.179.205] (helo=hephaestus.lan.complete.org)
 by glockenspiel.complete.org with esmtps
 (with TLS1.2:RSA_AES_128_CBC_SHA1:128)
 (TLS peer CN christoph.complete.org, certificate verified)
 (Exim 4.80) id 1YMqHG-0002vg-06
 for freebsd-questions@freebsd.org; Sat, 14 Feb 2015 21:53:50 -0600
Received: from [::1] by hephaestus.lan.complete.org with esmtp (Exim 4.84)
 (envelope-from <jgoerzen@complete.org>) id 1YMqHC-00037H-P7
 for freebsd-questions@freebsd.org; Sat, 14 Feb 2015 21:53:46 -0600
Message-ID: <54E01849.3020500@complete.org>
Date: Sat, 14 Feb 2015 21:53:45 -0600
From: John Goerzen <jgoerzen@complete.org>
User-Agent: Mozilla/5.0 (X11; Linux x86_64;
 rv:31.0) Gecko/20100101 Icedove/31.3.0
MIME-Version: 1.0
To: freebsd-questions@freebsd.org
Subject: 10.1 ZFS - why canmount=off for /usr and /var by default?
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions/>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 15 Feb 2015 03:53:52 -0000

So this is a fresh 10.1-RELEASE install, with the guided/automatic ZFS
setup on a single hard disk.  Couldn't be simpler, right?  Except
something is odd with /usr and /var.  Consider:

# zfs list | egrep 'NAME|usr'
NAME                 USED  AVAIL  REFER  MOUNTPOINT
zroot/usr            607M   216G    96K  /usr
zroot/usr/home       180K   216G   180K  /usr/home
zroot/usr/ports      607M   216G   607M  /usr/ports
zroot/usr/src         96K   216G    96K  /usr/src

Now, I've installed 5GB of packages into /usr/local.  There's no way
/usr is only using 607M.  So I thought, hmm, maybe they're not being
mounted.  And indeed:

# zfs list -o name,mountpoint,canmount,mounted | egrep 'NAME|no'
NAME                MOUNTPOINT  CANMOUNT  MOUNTED
zroot               none              on       no
zroot/ROOT          none              on       no
zroot/usr           /usr             off       no
zroot/var           /var             off       no

And, of course:

# df -h /usr/local
Filesystem            Size    Used   Avail Capacity  Mounted on
zroot/ROOT/default    220G    4.5G    216G     2%    /

(I have compress=3Dlz4 set for everything)

So, the next question is: why?  Why is there a /usr and a /var, which
show up in zfs list with a mountpoint of /usr and /var, but which aren't
being mounted?  Why is canmount=3Doff for these?  And if canmount=3Doff, =
why
give it a mountpoint which looks rather misleading in a zfs list?

I promise to stop asking questions soon! :-)

Thanks,

John