Bug#1070482: /tmp and tmpfs (was: Re: trixie upgrade guide)

Hi,

Thanks for your feedback.  I'm sending this to https://bugs.debian.org/1070482
since it's more useful there I guess.

In general, suggestions for improving the Debian trixie release notes are
useful if posted as bugs to the 'release-notes' pseudo-package.  Alternatively,
use our gitlab interface at salsa.debian.org.

Bye,

Joost

On Tue, May 20, 2025 at 06:43:05AM -0400, [email protected] wrote to
[email protected]:
> 
> Hello All,
> 
> I've been looking into testing trixie, and so looking here:
> 
> https://www.debian.org/releases/trixie/release-notes/upgrading.html
> 
> I know this may be a beta, non-current version.  Yet I'd like to express
> a desire to get something into this doc.  I'm happy to help if I can.
> 
> The /tmp -> tmpfs change is huge for me.  I suspect it's huge for many
> others.  The change is here, I'm not trying to alter this change, but
> Debian has always been about informed change whenever possible.
> 
> So from the perspective of someone that is used to the old behaviour for
> decades, a definitive, "from the source" guide about the change is key to
> me.  Not something gleamed from random posts around the net.
> 
> And it cannot be stressed how much this change will break some workflows.
> 
> So to mitigate impact, at the very least this change needs to be
> mentioned.
> 
> Questions I have, which are not clear to me and I believe should be
> covered in the doc:
> 
> 
> 1) What happens if /tmp fills up?
> 
> Does it automatically write to disk in some unknown place?  Or does it
> just throw an error?
> 
> 2) What are the defaults?
> 
> How much RAM is the default config set to?  Will it push stuff out of VM
> space?
> 
> 3) Are files still deleted upon boot or not?
> 
> It seems apparent, but validation is important
> 
> 4) How to work around this?
> 
> This is new in Trixie.  There are a myriad of workflows designed for old Debian defaults, including unarchiving TB sized archives into /tmp, expecting lock files to never change regardless of how long they are there, and far more.
> 
> It's OK that we don't all have the same workflow.  It doesn't matter what
> others do here.  All that matters is that this can greatly impact people,
> and they may need *months* to move to a config where stuff just vanishes
> from /tmp, or where stuff is too big for /tmp.
> 
> As with any other massive and huge change, Debian typically allows a
> release without breaking for the old behaviour.  A simple work around, to
> buy time, is to disable mounting tmpfs.
> 
> There should be a 'just do this', so that people aren't finding poor or
> disastrous ways randomly around the net.
> 
> 
> --
> 
> 
> Anyhow, that's my first walk through.  Once in install trixie on some
> machines, I'll have better insight.
> 
> 
>