Subject: Re: /etc/rc critical filesystem mount changes
To: None <M.Drochner@fz-juelich.de>
From: Curt Sampson <cjs@cynic.net>
List: current-users
Date: 04/01/1999 17:43:01
On Thu, 1 Apr 1999, Matthias Drochner wrote:

> cjs@cynic.net said:
> > What between the mount_critical_filesystems and the mount -a uses /var/
> > tmp?
> 
> Don't know... there is some stuff in between. Who knows what someone
> might want to do there.

Uh...we know what's there, since we wrote /etc/rc. If others are
modifying /etc/rc, they surely can modify the mount parts to
acommodate their own needs as well.

> > Oh, BTW, I'm not really sure that /var/tmp on MFS is a good idea;
> > generally /var/tmp is thought of as something that will persist
> > across reboots.
> 
> Yes - I know. But for a diskless box the speed gain is worth it.

Just a note: if this is for a compiler speed gain, set TMPDIR=/tmp
in the environment and it will use (your presumably mfs) /tmp,
rather than /var/tmp.

> > so that we don't have to move, e.g., /usr from one to the other based
> > whether it's a local or remote FS. That appears to me to be just one
> > more manual thing that the computer can do automatically. 
> 
> The computer doesn't do this very well. It doesn't deal with
> dependencies doe to mounts in subdirs or stacked mounts.

No, but keep in mind we're talking about a considerably simplified
situation here: just the file systems that are absolutely critical
to a small portion of the boot code. Most filesystems do not fall
into this category, and thus there's not a problem here.

I think it notable that nobody has come up with even a single
hypothetical example of a reasonable situation where the current
code breaks.

> Further, for diskless boxes the difference between "before
> network start" and "after network start" is rather small;
> I might prefer to mount critical stuff before "netstart".
> Even if the computer did it right in "almost all cases" or
> "the cases I consider reasonable" it should be easy to
> override.

In the end, it is. Just modify /etc/rc.

cjs
-- 
Curt Sampson  <cjs@cynic.net>   604 801 5335   De gustibus, aut bene aut nihil.
The most widely ported operating system in the world: http://www.netbsd.org