Re: Are 'guix gc' stats exaggerated?

[raingloom]

On 2024-05-26 22:13, Felix Lechner via "Development of GNU Guix and the
GNU System distribution." wrote:
> Hi,
> 
> Today I ran 'guix gc' on equipment with an ext4 root partition.  It had
> these space characteristics beforehand:
> 
>     Filesystem  Size       Used      Avail     Use% Mounted on
>     /dev/dm-3   309047680  157252980 138126064  54% /
> 
> or for human eyes:
> 
>     /dev/dm-3   295G        150G      132G      54% /
> 
> After the run, the drive showed:
> 
>     /dev/dm-3   309047680   88267956 207111088  30% /
> 
> or for human eyes:
> 
>     /dev/dm-3   295G         85G      198G      30% /
> 
> By my math, about 65.8 GiB were recovered.
> 
> When 'guix gc' was done, it announced:
> 
>     [184389 MiB] deleting '/gnu/store/...'
>     deleting `/gnu/store/trash'
>     deleting unused links...
>     note: currently hard linking saves 59224.03 MiB
>     guix gc: freed 110,649.49 MiBs
> 
> Seeing the 184389 MiB number, or 180 GiB, already made me suspicious.
> It exceeded my drive usage by 30 GiB.  Even the more conservative 110649
> MiB "freed," however, are off by a mile. That would have been 108 GiB,
> or 42 GiB more than the space actually recovered.
> 
> Am I looking at those numbers the wrong way?  Thanks!
> 
> Kind regards
> Felix

Are you using compression? (BTRFS, ZFS, etc)