Date: Sun, 15 Feb 2015 13:58:08 +0800 From: Ben Woods <woodsb02@gmail.com> To: John Goerzen <jgoerzen@complete.org> Cc: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: Re: 10.1 ZFS - why canmount=off for /usr and /var by default? Message-ID: <CAOc73CANPtOeTdyCbuyyVVJDbMMDqpYwTcXPk%2BqKy5vzL_br9Q@mail.gmail.com> In-Reply-To: <54E01849.3020500@complete.org> References: <54E01849.3020500@complete.org>
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To quote Allan Jude when I posed this question to him: "The /usr dataset has 'canmount' set to off. It only exists so that other datasets can be created under it. The idea here is that you want /usr/bin and /usr/local etc to be included in the / dataset, as that is the one used for boot environments. To use boot environments, you need to install the tool from the ports tree: sysutils/beadm-devel We'll discuss this more on the [bsdnow.tv] show, and maybe do a tutorial sometime soonish." In summary, the /usr and /var datasets will not actually have any files stored in them. Any sub-datasets that ARE mounted will have the files in them, and other files that sit under /usr or /var which are not in a sub-dataset will actually be stored in the zroot/ROOT/default dataset (and available for boot environments). -- From: Benjamin Woods woodsb02@gmail.com On 15 February 2015 at 11:53, John Goerzen <jgoerzen@complete.org> wrote: > > 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=lz4 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=off for these? And if canmount=off, why > give it a mountpoint which looks rather misleading in a zfs list? > > I promise to stop asking questions soon! :-) > > Thanks, > > John > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " freebsd-questions-unsubscribe@freebsd.org"
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