Subject: Re: bug#51787: GC takes more than 9 hours on berlin

From: Maxim Cournoyer <[email-masked]>
Date: Wed, 16 Aug 2023 06:53:05 -0400

Hi,

Mathieu Othacehe <[email-masked]> writes:

> Hello,
>
> On berlin, the daily GC command is still running whereas it was started
> 9 hours ago.
>
> guix processes
> [...]
> SessionPID: 37231
> ClientPID: 37195
> ClientCommand: /gnu/store/49vfv8l1j96bbd73ssbqanpnjz83arss-guix-1.3.0-11.014f1b6/libexec/guix/guile \ /gnu/store/49vfv8l1j96bbd73ssbqanpnjz83arss-guix-1.3.0-11.014f1b6/bin/guix gc -F10995116277760
>
>
> and
>
> mathieu@berlin ~$ ps auxww|grep 37195
> root      37195  0.0  0.0 183260 33440 ?        Sl   03:59   0:00 /gnu/store/49vfv8l1j96bbd73ssbqanpnjz83arss-guix-1.3.0-11.014f1b6/libexec/guix/guile \ /gnu/store/49vfv8l1j96bbd73ssbqanpnjz83arss-guix-1.3.0-11.014f1b6/bin/guix gc -F10995116277760
>
>
> That's really problematic as it is blocking some other berlin services
> such as Cuirass, which has 4564 packages in its fetch queue:
>
> mathieu@berlin ~$ less /var/log/cuirass-remote-server.log
> [...]
> 2021-11-12T12:47:01 period update: 0 resumable, 0 failed builds.
> 2021-11-12T12:47:01 period update: 4564 items in the fetch queue.

I'm more than happy to close this old, no longer relevant bug :-).

Since it was reported, the storage was migrated to a much faster array,
and is using the Btrfs file system with zstd compression, which avoids
the inodes exhaustion issue we've had with ext4 in the past.

A full garbage collection (GC) is run daily to keep the store growth in
check and for the GC to always take a similar amount of time (less than
20 minutes) every day.

-- 
Thanks,
Maxim