Re: GC strategy on clusters

["Ludovic Courtès" <ludovic.courtes@inria.fr>]

Hi,

zimoun <zimon.toutoune@gmail.com> skribis:

>> It depends.  A practical use case I have in mind: you run experiments,
>> you submit a paper including its results, you get initial reviews months
>> later, and even later it’s published and you get to present it.  At that
>> point, you want to answer questions and to reproduce it.  4–6 months is
>> not a lot in that context.
>
> To add another data point.  Even it is hard to have a good overview, I
> would say the average is 2-4 years for a typical project.  It is hard
> because currently all is not done with the same tools for the same
> task.  For instance, some data is cleaned with some tools, then an
> partial analysis is done, months later another data is added so
> another partial analysis with probably different tools, then months
> later a full toolsuite as Bioconductor (or whatever) is updated and
> some analysis are re-done.  The final publication is a mix of all over
> the 2-4 years project with details at various level.

Right.

>> Good points.  Hopefully “sources go missing” can soon be considered
>> addressed.  Really, failing TLS tests is the most worrisome issue to me
>> because we don’t have any idea on how to address it systematically.
>
> By "soon", you mean the bricks are there and it is missing to glue
> them together.  From my opinion, some details need to be addressed to
> have a full end-to-end sources fallback, since evil is hidden inside
> the details. ;-)

True!  I’m really hopeful about the Disarchive/SWH combination, together
with <https://guix.gnu.org/sources.json>.  Of course we’ll have to
monitor that, and we can expect bumps on the road :-), but at least we
have a plan.

> About the TLS, you proposed to setup a machine ahead of clock.  Maybe
> it is worth to try.

Oh sure, that trick definitely works.  But it’s a terrible hack, and it
means that, by default, people will just fail to build the package.

> Well, when we discussed the '--list-profiles', it was initially for my
> personal purposes.  Then, I have tried to use it to monitor the few
> users that I have.  Well, in Biology they have the concept of "-80
> fridge".  It is a big and very cold fridge where you keep samples,
> potentially for a long time.  Everybody put in until it is full and
> once it is full, there is endless discussion on what to throw... until
> the fridge is broken because shutdown or unexpected failures and then
> it is obvious to everybody what needs to be taken or thrown.  I am
> using such analogy to explain the hygiene to have on shared machines
> Hum, once written I do not know if it relevant. ;-)

It surely is.  :-)  I mean, I didn’t even think about it until GC
couldn’t make any progress.

> From my point of view, having a channel+manifest "backup" for old
> profiles seems something to try.  It cost nothing with
> ''--export-manifest" and "--export-channels".

Yes, though it’s an approximation; so it should only be used when we
know that it’s 100% faithful, as is the case for ‘guix pull’ profiles.

Ludo’.