Subject: [bug#51427] [PATCH] nix: libstore: Do not remove unused links when deleting specific items.

From: Jack Hill <[email-masked]>
Date: Mon, 8 Nov 2021 23:57:23 -0500 (EST)

On Mon, 8 Nov 2021, Maxim Cournoyer wrote:

> Ludovic Courtès <[email-masked]> writes:
>
>> BTW, those using Btrfs can probably use ‘--disable-deduplication’ and be
>> done with it.
>
> I erroneously used to think that Btrfs could do live deduplication, but
> it doesn't.  There are external tools to do out of band / batch
> deduplication though [0]; so if they perform better than the guix daemon's
> own dedup, perhaps we could document this way out for our Btrfs users.
>
> [0]  https://btrfs.wiki.kernel.org/index.php/Deduplication

A little while ago I had hoped to test btrfs with --disable-deduplication 
and bees [1] as the deduplication agent, but wasn't able to successfully 
run a system with --disable-deduplication because I needed the 
deduplication to cover up problem with grafts [2]. Until we resolve the 
second issue, I don't think we should recommend folks run the daemon with 
--disable-deduplication.

[1] https://issues.guix.gnu.org/47983 (still missing a service)
[2] https://issues.guix.gnu.org/47115

Best,
Jack