Re: Postmortem of service downtime

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> From Sunday May 19th to Tuesday may 21st, for about 36h,
> bayfront.guix.gnu.org, the machine behind many services went down:
>
>   https://lists.gnu.org/archive/html/info-guix/2024-05/msg00000.html
>
> Affected web sites and services included:
>
>   guix.gnu.org
>   bordeaux.guix.gnu.org
>   logs.guix.gnu.org
>   hpc.guix.info
>   foundation.guix.info
>   packages.guix.gnu.org
>   qa.guix.gnu.org
>

[...]

>     A large part of the slowness was due to ‘guix substitute’ reading
>     all the 300K+ entries from /var/guix/substitute/cache and deleting
>     them, one by one (this took several minutes).  Chris had mentioned
>     that performance issue in the past; it’s not much of a problem on
>     one’s laptop with an SSD, but it’s clearly a problem here where
>     there are more entries than usual.  We should at least drastically
>     reduce the TTL of cache entries.

Interesting!

>   • qa-frontpage failed to build when we first reconfigured the machine,
>     so we commented it out.  This is now fixed:
>
>       https://git.savannah.gnu.org/cgit/guix/maintenance.git/commit/?id=3fecb1e8fdea65a7440fec403c1c52da197b5dfe
>
>   • guix-packages-website (the server behind packages.guix.gnu.org)
>     still refuses to start with an Artanis error:
>
>       https://issues.guix.gnu.org/71138
>
> Ludo’, on behalf on the emergency rescue^W^W sysadmin team.

Phew!  Thanks for the detailed write-up and for the fixes/thankless work
of bringing the machine back up and running.

-- 
Maxim