From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: Ricardo Wurmus <rekado@elephly.net>, guix-devel <guix-devel@gnu.org>
Subject: Re: Building and caching old Guix derivations for a faster time machine
Date: Fri, 17 Nov 2023 23:27:33 -0500 [thread overview]
Message-ID: <877cmfd6tm.fsf@gmail.com> (raw)
In-Reply-To: <878r6xu2pe.fsf@gnu.org> ("Ludovic Courtès"'s message of "Thu, 16 Nov 2023 16:39:57 +0100")
Hi,
Ludovic Courtès <ludo@gnu.org> writes:
> Hi,
>
> Ricardo Wurmus <rekado@elephly.net> skribis:
>
>> to me the biggest downside of using “guix time-machine” is that it has
>> to do a lot of boring work before the interesting work begins. The
>> boring work includes building Guix derivations for the given channels,
>> most of which have long been collected as garbage on ci.guix.gnu.org.
>>
>> It would be helpful, I think, to more aggressively cache these
>> derivations and their outputs, and to go back in time and build the
>> derivatinons for past revisions of Guix. I would expect there to be a
>> lot of overlap in the produced files, so perhaps it won’t cost all that
>> much in terms of storage.
>>
>> What do you think?
>
> I agree. The ‘guix publish’ TTL¹ at ci.guix was increased to 180 days
> following <https://issues.guix.gnu.org/48926> in 2021. That’s still not
> that much and these days and right now we have 84 TiB free at ci.guix.
>
> I guess we can afford increasing the TTL, probably starting with, say,
> 300 days, and monitoring disk usage.
>
> WDYT?
While the 84 TiB we have at our disposal is indeed lot, I'd rather we
keep the TTL at 180 days, to keep things more manageable for backup/sync
purposes. Our current TTL currently yields 7 TiB of compressed NARs,
which fits nicely into the hydra-guix-129 10 TiB slice available for
local/simple redundancy (it's still on my TODO, missing the copy bit).
I've been meaning to document an easy mirroring setup for that
/var/cache/guix/publish directory, and having 14 TiB instead of 7 TiB
there would hurt such setups.
Perhaps a compromise we could do is drop yet another compression format?
We carry both Zstd and LZMA for Berlin, which I see little value in; if
we carried only ZSTD archives we could probably continue having < 10 TiB
of NARs for a TTL of 360 days (although having only 3.5 TiB of NARs to
sync around for mirrors would be great too!).
What do you think?
--
Thanks,
Maxim
next prev parent reply other threads:[~2023-11-18 4:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-10 9:29 Building and caching old Guix derivations for a faster time machine Ricardo Wurmus
2023-11-16 9:59 ` Simon Tournier
2023-11-16 15:39 ` Ludovic Courtès
2023-11-18 4:27 ` Maxim Cournoyer [this message]
2023-11-22 18:27 ` Ludovic Courtès
2023-11-29 16:34 ` Simon Tournier
2023-11-30 13:28 ` Maxim Cournoyer
2023-11-30 14:05 ` Guillaume Le Vaillant
2023-12-05 1:18 ` Maxim Cournoyer
2024-01-12 9:56 ` Simon Tournier
2024-01-15 4:02 ` Maxim Cournoyer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://guix.gnu.org/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=877cmfd6tm.fsf@gmail.com \
--to=maxim.cournoyer@gmail.com \
--cc=guix-devel@gnu.org \
--cc=ludo@gnu.org \
--cc=rekado@elephly.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/guix.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).