From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp0 ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id 4G4dKmWd1F6YFwAA0tVLHw (envelope-from ) for ; Mon, 01 Jun 2020 06:17:09 +0000 Received: from aspmx2.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp0 with LMTPS id qP38JWWd1F4DSwAA1q6Kng (envelope-from ) for ; Mon, 01 Jun 2020 06:17:09 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx2.migadu.com (Postfix) with ESMTPS id ED2496804C4 for ; Mon, 1 Jun 2020 06:17:08 +0000 (UTC) Received: from localhost ([::1]:49628 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jfdkx-0003HA-Of for larch@yhetil.org; Mon, 01 Jun 2020 02:17:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40008) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jfdks-0003Gy-GL for guix-patches@gnu.org; Mon, 01 Jun 2020 02:17:02 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:51024) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jfdks-0000LP-5o for guix-patches@gnu.org; Mon, 01 Jun 2020 02:17:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jfdkr-0004U1-Vt for guix-patches@gnu.org; Mon, 01 Jun 2020 02:17:01 -0400 X-Loop: help-debbugs@gnu.org Subject: [bug#40236] [PATCH] doc: Suggest Btrfs with compression instead of ext4 for root partition. Resent-From: Efraim Flashner Original-Sender: "Debbugs-submit" Resent-CC: guix-patches@gnu.org Resent-Date: Mon, 01 Jun 2020 06:17:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 40236 X-GNU-PR-Package: guix-patches X-GNU-PR-Keywords: patch To: Maxim Cournoyer Cc: Ludovic =?UTF-8?Q?Court=C3=A8s?= , Pierre Neidhardt , 40236@debbugs.gnu.org, Jonathan Brielmaier Received: via spool by 40236-submit@debbugs.gnu.org id=B40236.159099220317206 (code B ref 40236); Mon, 01 Jun 2020 06:17:01 +0000 Received: (at 40236) by debbugs.gnu.org; 1 Jun 2020 06:16:43 +0000 Received: from localhost ([127.0.0.1]:34337 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jfdkZ-0004TS-AO for submit@debbugs.gnu.org; Mon, 01 Jun 2020 02:16:43 -0400 Received: from flashner.co.il ([178.62.234.194]:47462) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jfdkY-0004TD-4w for 40236@debbugs.gnu.org; Mon, 01 Jun 2020 02:16:42 -0400 Received: from localhost (unknown [188.120.128.90]) by flashner.co.il (Postfix) with ESMTPSA id 4BAFC40031; Mon, 1 Jun 2020 06:16:36 +0000 (UTC) Date: Mon, 1 Jun 2020 09:16:03 +0300 From: Efraim Flashner Message-ID: <20200601061603.GF7397@E5400> References: <87o8s2k6lr.fsf@gmail.com> <20200409201244.GR1518@E5400> <87o8rzvlg9.fsf@ambrevar.xyz> <20200410082425.GA1518@E5400> <87eesvvhim.fsf@ambrevar.xyz> <87h7xmiz96.fsf@gmail.com> <87lfmya78b.fsf@ambrevar.xyz> <87y2p83650.fsf@ambrevar.xyz> <20200531075532.GD7397@E5400> <878sh75scf.fsf@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="IbVRjBtIbJdbeK1C" Content-Disposition: inline In-Reply-To: <878sh75scf.fsf@gmail.com> X-PGP-Key-ID: 0x41AAE7DCCA3D8351 X-PGP-Key: https://flashner.co.il/~efraim/efraim_flashner.asc X-PGP-Fingerprint: A28B F40C 3E55 1372 662D 14F7 41AA E7DC CA3D 8351 X-Spam-Score: -0.0 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-Spam-Score: -1.0 (-) X-BeenThere: guix-patches@gnu.org List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-patches-bounces+larch=yhetil.org@gnu.org Sender: "Guix-patches" X-Scanner: scn0 Authentication-Results: aspmx2.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx2.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Spam-Score: -1.11 X-TUID: bnqMlP9PS0Y9 --IbVRjBtIbJdbeK1C Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > > > > Two more things: > > /var/guix/db should probably have CoW disabled, as should /tmp >=20 > I haven't bothered and my system seems to be doing OK. When I asked in > #btrfs, people told me to keep CoW unless I was really sure it was a > problem (i.e., run benchmarks), as it implies loosing the checksum > validation and compression. The command 'man 5 btrfs' also states that > "Updates in-place improve performance for workloads that do frequent > overwrites, at the cost of potential partial writes, in case the write > is interrupted (system crash, device failure).", which doesn't sound > safe to do for something as important as /var/guix/db. Fair enough. I had heard that the CoW stuff wasn't great for databases. I thought Leo ran into some issues with CoW on /tmp with the syncthing tests. > > would the deduplication of btrfs be "better" than the deduplication from > > the daemon? >=20 > On my system (with zstd compression), compsize -x /gnu/store suggests > a resounding yes: >=20 > --8<---------------cut here---------------start------------->8--- > sudo compsize -x /gnu/store > Processed 3479664 files, 954748 regular extents (3002677 refs), 1451082 i= nline. > Type Perc Disk Usage Uncompressed Referenced > TOTAL 57% 51G 88G 217G > none 100% 32G 32G 81G > zstd 33% 18G 56G 135G > --8<---------------cut here---------------end--------------->8--- >=20 > The delta between the Uncompressed and Referenced column is attributed > to the deduplication done by Btrfs, and provides massive space savings > in my case (this is just for /gnu/store). >=20 > I'd need 217 GiB over a traditional fs such as EXT4 to hold my current > store, while an uncompressed Btrfs partition would use only 88 GiB. > With zstd compression, it's down to 51 GiB, or less that a quarter of > what would have been required using EXT4. I always understood that as with compression you're using 51G instead of 88G, and because of deduplication from the daemon it would only be 88G instead of 217G. I took the numbers from 'none' to mean that the daemon itself already did a lot of deduplication. --=20 Efraim Flashner =D7=90=D7=A4=D7=A8=D7=99=D7=9D = =D7=A4=D7=9C=D7=A9=D7=A0=D7=A8 GPG key =3D A28B F40C 3E55 1372 662D 14F7 41AA E7DC CA3D 8351 Confidentiality cannot be guaranteed on emails sent or received unencrypted --IbVRjBtIbJdbeK1C Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEoov0DD5VE3JmLRT3Qarn3Mo9g1EFAl7UnSEACgkQQarn3Mo9 g1EE5hAAuGcXvkbF5BXgMclCQtt877SfEjC8fUE4eylRgb1Zz3d5gq5WEHRDClDl M1hXg8QvNZoRO1g3LqSinfUqY2cU7VTKA/qQ1BOw7UE2xoXqNeAPtWKZ7aZHbt3U /v+mIRvOKV/IAVrQq8jTcuP6N/3x/aQxfenNXNm8fbVVioiB3Ujg+BPJniK6jR9P +Z9RbL+swXAt5jTpln6cL3pvthoNnGlOw7HQ1nG/onV3i5H3A3sKqPRb2KnwO1jI qL+l7PEf3H4yfw5C4Xp1uqn5pooI/AnIL/VesLBbyUz43OP/7yAMFBH3MYavj65w 2hmI564zAHfgl/3JJ9JYlXKmi2qBr4fFepHggi2vOg03uW/iSvRWXNuO0QDG8Gtl 5uZuZF8E08jviDYwCJCyUSPIDFRcScxsu4LkedpzRQKnkhgzqC2lbWG//fFPqI7W QLiOdXsD7nDzQiLNg8NBfb6KN+HIA5jYn6lWCbbk2L39t8AgBHAxdvK1/ENzYSv6 Gc0rExt+g2i8uQvj86zHcmMc9IIowpTmRTyWaFfoo3QIKWfB7c6JbNIktTxdwk5w t1FcmlFm1ukqvQbaWL5gaQRTfitH1ieCJ2TDB8YsP5+qsiSnh1AqzIIPRNG2LsZA Jm4O10fZGIoL7c9+HKGwuSDGZUr+4beauBccmzdC2NM1DbcDHPQ= =R68v -----END PGP SIGNATURE----- --IbVRjBtIbJdbeK1C--