Re: create /tmp with ffs vs. tmpfs ?

[Steve Rikli <sr%genyosha.net@localhost>]

On Mon, Aug 12, 2024 at 10:36:19AM +0200, Martin Husemann wrote:
> On Sun, Aug 11, 2024 at 06:54:55PM -0700, Steve Rikli wrote:
> > I'm re-installing several old and new systems with NetBSD 10.0, one of
> > them is a 32-bit ITX PC, with VIA C7 CPU.
> > 
> > It has small memory (1GB max) but plenty of disk (128GB SSD). sysinst
> > says default size of "25%" for /tmp; from experimenting with other PC's,
> > I believe that's "25% of main memory" (RAM) with tmpfs.
> 
> Yes.
> 
> ...
> > 2) can I configure /tmp as ffs rather than tmpfs?
> 
> Yes, but in that case you may consider not making /tmp a separate mount
> point (in sysinst: set size to 0). This removes the size limit - which
> may be good or bad, depending on your usage.

I don't follow you.  You're saying if I make /tmp separate, I may not be
able to make it as large as I want?

Or maybe you're pointing out the "25%" etc. sizing behaviors of the
NetBSD sysinst; I hadn't quite worked out how exactly to make the
non-default /tmp partition in sysinst -- so far I've just been using the
"Set sizes of NetBSD partitions" menu selector, but I also see "Manually
define partitions" and other things, so I figured I'd be able to find a
sufficient hammer with some more poking around.

Things have changed a bit since I was running NetBSD 2.0 on SPARC. ;-)

IME it's (subjectively) better to have /tmp be separate from / e.g. to
avoid filling your root partition if things go awry from userland. I
typically make /var a separate partition for the same reason.

I.e. my typical partition map is /, swap, /var, /tmp, along with any
user or application-y areas (e.g. /home), plus whatever bootloader-ish
areas might be needed for EFI, GPT et al.

Needs more experimentation....  :-)

Thanks,
sr.