10.1 ZFS - why canmount=off for /usr and /var by default?

[John Goerzen]

Yep.  Even if the dataset exists, all the benefits of it could still be
obtained without setting mointpoint=.  I find mountpoint= to be
misleading for a dataset where canmount is off.

John

On 02/23/2015 08:36 AM, krad wrote:
> It makes a degree of sense, however what are the properties most
> people set to inherit? Compression, atime, for me and I do that at the
> root dataset anyway, and sometimes dedup if its an ssd based pool.
>
> I still dont see why we set the mountpoint as this just confuses imho
>
> On 19 February 2015 at 15:49, Trond Endrestøl
> <Trond.Endrestol at fagskolen.gjovik.no
> <mailto:Trond.Endrestol at fagskolen.gjovik.no>> wrote:
>
>     On Thu, 19 Feb 2015 12:06-0000, krad wrote:
>
>     > It is a bit confusing, I have to ask why call it zroot/usr at
>     all? I use
>     > <pool>/os/ for stuff like ports etc and then set the mountpoint.
>     If we must
>     > use usr in the name why not set the mountpoint to legacy as
>     well, as its
>     > more clearly not used?
>
>     Sorry for jumping in, but it's done simply to inherit the mountpoint.
>
>     It has already been said, but here's a recap.
>
>     Most of what you'll find in /usr belongs to the current BE. Datasets
>     create below zroot/usr, e.g. zroot/usr/local, magically appears as
>     /usr/foo, e.g. /usr/local. The same goes for zroot/var and /var.
>
>     If you want to install FreeBSD with ZFS using some other train of
>     thought, then feel free to do so.
>
>     I have my own set of scripts at
>     http://ximalas.info/~trond/create-zfs/canmount/
>     <http://ximalas.info/%7Etrond/create-zfs/canmount/>, and they
>     certainly
>     have their flaws, and maybe I even change these scripts in the future
>     as I move along and change my perspective on FreeBSD and ZFS.
>
>     > On 15 February 2015 at 13:52, John Goerzen
>     <jgoerzen at complete.org <mailto:jgoerzen at complete.org>> wrote:
>     >
>     > > Ben Woods <woodsb02 <at> gmail.com <http://gmail.com>> writes:
>     > >
>     > > >
>     > > > 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.
>     > >
>     > > That makes sense.  But it is misleading to have the mountpoint
>     set to /usr
>     > > and /var, isn't it?  In a zfs list, it looks as if it's being
>     used for /usr
>     > > and /var, when really as you say it's a container.
>     > >
>     > > I wonder - would there be a place I could submit a bug report
>     to suggest
>     > > that the mountpoint property be inherited at the default
>     rather than set
>     > > for
>     > > these two filesystems?
>     > >
>     > > > To use boot environments, you need to install the tool from
>     the ports
>     > > tree:
>     > > > sysutils/beadm-devel
>     > >
>     > > Interesting.  That looks quite nice.  I need to read up a bit
>     more on it,
>     > > clearly, since it seems to be more than just a zfs clone and
>     zpool set
>     > > bootfs that I was expecting.
>     > >
>     > > Thanks,
>     > >
>     > > John
>
>     --
>     +-------------------------------+------------------------------------+
>     | Vennlig hilsen,               | Best regards,                      |
>     | Trond Endrestøl,              | Trond Endrestøl,                   |
>     | IT-ansvarlig,                 | System administrator,              |
>     | Fagskolen Innlandet,          | Gjøvik Technical College, Norway,  |
>     | tlf. mob.   952 62 567,       | Cellular...: +47 952 62 567
>     <tel:%2B47%20952%2062%20567>,       |
>     | sentralbord 61 14 54 00.      | Switchboard: +47 61 14 54 00
>     <tel:%2B47%2061%2014%2054%2000>.      |
>     +-------------------------------+------------------------------------+
>
>