Re: Are 'guix gc' stats exaggerated?

[Ludovic Courtès]

Hi Felix,

Felix Lechner via "Development of GNU Guix and the GNU System
distribution." <guix-devel@gnu.org> skribis:

> It probably makes more sense to focus on the Guix daemon here.  I hope
> you don't mind a few clarifying questions.
>
> Why, please, does the benefit of de-duplication approach a fixed ratio
> of 3:1?  Does the benefit not depend on the number of copies in the
> store, which can vary by any number?  (It sounds like the answer may
> have something to do with store size.)

Where does that 3:1 figure come from?

> Further, why is the removal of hardlinks counted as saving space even
> when their inode reference count, which is widely available [1] is
> greater than one?

Where do you see that in the code?  After checking ‘removeUnusedLinks’,
I think it counts space savings right.  (OTOH, something somewhere is
counted wrong, as anyone who’s used ‘guix gc -F…’ has seen; not sure
where the bug is!)

Thanks,
Ludo’.