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

[Trond Endrestøl]

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/, 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> wrote:
> 
> > Ben Woods <woodsb02 <at> 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

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