Re: Building and caching old Guix derivations for a faster time machine

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Simon,

Simon Tournier <zimon.toutoune@gmail.com> writes:

> Hi,
>
> On mer., 22 nov. 2023 at 19:27, Ludovic Courtès <ludo@gnu.org> wrote:
>
>> For long-term storage though, we could choose to keep lzip only (because
>> it compresses better).  Not something we can really do with the current
>> ‘guix publish’ setup though.
>
> It looks good to me.  For me, the priority list looks like:

I'd like to have a single archive type as well in the future, but I'd
settle on Zstd, not lzip, because it's faster to compress and
decompress, and its compression ratio is not that different when using
its highest level (19).

>  1. Keep for as longer as we can all the requirements for running Guix
>  itself, e.g., “guix time-machine”.  Keep all the dependencies and all
>  the outputs of derivations.  At least, for all the ones the build farms
>  are already building.
>
>  2. Keep for 3-5 years all the outputs for specific Guix revision, as
>  v1.0, v1.1, v1.2, v1.3, v1.4.  And some few others.

That'd be nice, but not presently doable as we can't fine tune retention
for a particular 'derivation' and its inputs in the Cuirass
configuration, unless I've missed it.

-- 
Thanks,
Maxim