Re: Architecture baseline for Forky

Hi all,

On Mon, 27 Oct 2025, at 19:22, Colin Watson wrote:
> CERN spoke at DebConf [1] and indicated that ~47% of their accelerator=20
> control fleet runs x86-64-v1, which due to a cascading series of=20
> replacement costs meant that they estimated a budget of about =E2=82=AC=
7M to=20
> migrate from CentOS 7 to CentOS Streams 9.  As a result they chose to=20
> switch to Debian instead, and they said that their plan A was to use=20
> trixie and upgrade to forky in 2030.  If I understood them correctly,=20
> they did say (in the Q&A) that there was a plan to upgrade to at least=20
> x86-64-v2 in the 2034 long shutdown, but that it was still a complex=20
> project with the possibility of being derailed by operational issues.
>
> Has anyone consulted with them about how this would affect their plans=
? =20
> They're a pretty significant organization and I know a lot of Debian=20
> developers would like to keep them being able to use Debian.

I am one of the presenters of said talk :) Thanks for the mention.
=20
<CERN engineer hat on>
To give our perspective, as you mentioned correctly, we have numerous v1=
 machines that we'd love to upgrade by 2030, but it is very challenging.=
 If this change is adopted for Forky it'll put a wrench in our "Plan A",=
 which was to follow the Debian LTS release cycle and instead will have =
to freeze our infrastructure to Trixie until LS4 (2034). It'd also put a=
 question mark into our choice of Debian as the distribution for our mos=
t heterogeneous class of systems. The change in RedHat was a bit surpris=
ing but as a "server-focused" OS we could justify why it was made. We th=
en picked Debian in part because of its focus into compatibility with a =
wide range of systems, from x86 to embedded devices, only to be having t=
he same discussion now.
</CERN engineer hat off>

<DM Hat on>
My opinion as a DM and Debian user is that this is a change that will ha=
ve to be carefully evaluated, do we have any tests or benchmarks on what=
 are the benefits, performance or otherwise? There have been many respon=
ses to this thread already outlining all of the arguments on both sides,=
 so I will not repeat them here, but my opinion is that until now with e=
very machine I picked up I would never question "can it run Linux/Debian=
?", it was always a given. Reading the arguments on both sides, I tend t=
o agree on the fact that we should aim to support as many systems as pos=
sible as long as it is feasible. Then again, if something drastic happen=
s like kernel upstream decides to drop support for these architecture ve=
rsions, then it can be re-discussed. Required effort vs benefit and all =
that.

However, even the Debian website seems to have quite a few mentions to t=
hat effect as well[1].

" Windows 10 support ends in October 2025. Your computer may not run Win=
dows 11, but it will run Debian for many more years without buying new h=
ardware. Debian supports the End of 10 campaign."

"Debian has extensive Hardware Support.
    Most hardware is supported by the Linux kernel which means that Debi=
an will support it as well"
</DM Hat off>

I'll keep a keen eye on how this thread evolves. I'm open to hear any ar=
guments for/against the above.

Cheers,
Nikos

[1] https://www.debian.org/intro/why_debian

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