Re: [PATCH 2/2] btrfs: defrag: allow fine-tuning on lone extent defrag behavior

[Christoph Anton Mitterer <calestyo@scientia.org>]

On Wed, 2024-02-07 at 12:27 +0000, Filipe Manana wrote:
> A percentage, in the integer range from 1 to 99% for example, is a
> lot
> more user friendly, intuitive, obvious.

If by that you'd mean the percentage of wasted storage, then I'm not
really sure whether I can agree to that.

Especially percentage of what? The original untruncated extent size?
The user would never really know what that is.


If I have e.g. a 10.000 files with extent sizes of 1 GB, then 10%
wasted may already be too much for me.

But if I had 10.000 files with extents sizes of 1MB, the same 10% may
not be that much of a problem.

OTOH, if I have  10 million files with extent sizes of a few kB, than
even 1% might be already too much.



If the clean up of such wasted space is a manual operation, then I
would be best if one could somehow see not only how much is wasted
(which can, to some extent already be done via compsize) but also some
estimates how that is distributed like in the examples above... and
from that, which precentage or ratio or whatever one has to specify for
clean up to get so and so much wasted storage back.



Cheers
Chris.