From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 2A34E13877A for ; Fri, 20 Jun 2014 10:07:22 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 4E3A6E088F; Fri, 20 Jun 2014 10:07:16 +0000 (UTC) Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 25D9CE082B for ; Fri, 20 Jun 2014 10:07:15 +0000 (UTC) Received: from marcec ([77.22.138.176]) by mail.gmx.com (mrgmx001) with ESMTPSA (Nemesis) id 0M8NBi-1WlV8k1xvW-00vx6i for ; Fri, 20 Jun 2014 12:07:13 +0200 Date: Fri, 20 Jun 2014 12:07:00 +0200 From: Marc Joliet To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] btrfs: subvol without compression Message-ID: <20140620120700.73303d6c@marcec> In-Reply-To: <53A020A8.2070809@xunil.at> References: <53A020A8.2070809@xunil.at> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/pPcHsFceYszgzOj4ExmJMCa"; protocol="application/pgp-signature" X-Provags-ID: V03:K0:PP8FhG9jsHDNwZK40AQr7GDfvpRWSPWB5D6hhvwVUOwAdN9xdj8 flZhnhLbz7aMmEtDXCzDp0Dx/oxgSd+E9in7T776OB8UO5Oy+JFyIxneiw8IPT+HdQc2QCe TN6+eOHw+k763dSyolLk5MdqwosiN8ur/xBbL/kdvwXRMCJp5w/dpgeUpKVJ5XLvNHpjKWT im0a8pc/S/MNzRfBbqgSg== X-Archives-Salt: 81e381c0-5a1b-4e03-bc66-210f69e0d7d4 X-Archives-Hash: 806bc8eb10df00c3dec24fb99bc5161e --Sig_/pPcHsFceYszgzOj4ExmJMCa Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable I don't know if you eventually found an answer yourself, but since nobody e= lse has replied, here's what I found: Am Tue, 17 Jun 2014 13:04:08 +0200 schrieb "Stefan G. Weichinger" : >=20 > ... I am quite happy now with the performance of that new server I am > preparing. >=20 > See thread "Intel(R) C600 SAS Controller" for that story: >=20 > https://www.mail-archive.com/gentoo-user@lists.gentoo.org/msg146119.html >=20 > Right now I get quite good results when doing backups of the 2 existing > VMs (which have their virtio-disks on LVM-LVs on the host) ... up to > 200MB/s ... I can show for reference, if someone is interested. >=20 > I think that is around the possible maximum. >=20 > ---> >=20 > The issue I want to share with you is related to a btrfs subvol I have he= re. >=20 > Block device sda builds the btrfs-pool containing the root-fs: >=20 > # btrfs fi show > Label: ROOT uuid: 9133c469-df1e-45f5-a09f-d1b9c75c69da > Total devices 1 FS bytes used 29.47GiB > devid 1 size 500.00GiB used 278.04GiB path /dev/sda >=20 > Btrfs v3.12 >=20 > These are the subvolumes (I could/should rm some, but it doesn't matter > for this issue, afaik): >=20 > # btrfs su list / > ID 257 gen 4282 top level 5 path __active > ID 258 gen 4874 top level 5 path __active/root > ID 266 gen 4772 top level 258 path images > ID 267 gen 838 top level 258 path images/otrs > ID 289 gen 4285 top level 258 path images/windows > ID 538 gen 4874 top level 5 path __active/virt-backup >=20 >=20 > fstab has: >=20 > # grep btrfs /etc/fstab > LABEL=3DROOT / btrfs defaults,noatime,compress=3Dlzo 0 0 > LABEL=3DROOT /mnt/virt-backup btrfs compress=3Dno,noatime,subvolid=3D538 = 0 0 >=20 >=20 > ... so I want to mount subvolid 538 with disabled compression (to speed > up backups as the files written to it are compressed on the fly via pigz > already). So far nothing in particular stands out, that is, it looks like everything = is correct. > But after booting I get that dir mounted with compress=3Dlzo (which is > default). >=20 > # mount | grep btrfs > /dev/sda on / type btrfs (rw,noatime,compress=3Dlzo,space_cache) > /dev/sda on /mnt/virt-backup type btrfs > (rw,noatime,compress=3Dlzo,space_cache) >=20 > remounting works, though: >=20 > booze ~ # mount -o remount,compress=3Dno /mnt/virt-backup/ >=20 > booze ~ # mount | grep btrfs > /dev/sda on / type btrfs (rw,noatime,space_cache) > /dev/sda on /mnt/virt-backup type btrfs (rw,noatime,space_cache) >=20 > BUT it remounts / without compression as well ... ! >=20 > Is it a bug? A mistake or misunderstanding? =46rom my own google search, at least up to 2011 per-subvolume compression settings were not possible. Then, after subsequently searching on the btrfs wiki for a while, I finally found an answer: no. See this FAQ entry: https://btrfs.wiki.kernel.org/index.php/FAQ#Can_I_mount_subvolumes_with_dif= ferent_mount_options.3F [...] HTH --=20 Marc Joliet -- "People who think they know everything really annoy those of us who know we don't" - Bjarne Stroustrup --Sig_/pPcHsFceYszgzOj4ExmJMCa Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJTpAfNAAoJEL/Q5oYsiHj0Yy4QAIsOi6oJTz9QSLbfRarh0ktR Wlr+QrejfAoIsqn12tERK8iLnzQjeqbAFu1ihlRyVj0wELn9S1E0v+zN8s3vqsSG 6mY7/QP6VDna3lFkXYGd2IQkH4v41gQeYVLhy0MEWjwiaeiCiJ7KxhWLe4+vlUaz PZ5Ts7pxSEu5dtTIFeIXa+dXvkYJARkFp8PnkPdTv72qKnzM907YJkXvhdVc1xvw rOqLziuMb9yi4y2uHWdr1qNexYj5l0OHI0oodIADdJkMs8CVDGRu+LkAzmFPOPCF jTq4/mDh82EbHL9bzz14/FeG5fQ0IGVko7rquJ6c+Xe/bC8+1Jui9BI4WVrSX8uT uQzFfRTO2Ig9Itx57qpK7p0cWwWeMCnXXEkoWR9bIp7kB4sO5yF+Ky9+1ir8Xy8b F4BBEIEKkUvtwFmi+mCK9VNhY6ys0g48yL06QkUMVxy+rxj4/uf57MvjyXUDiC0R /ov/NnTWlYgc2tBckE6ZBWkbSAjAPfYk8OMmWfJt6nJdboZJXp36iIXRzUr4nHjJ poca334PaAVu59jakEg+c3HBiFAo513/JFHC4sjOmyBmw/O2+WoM5vVuyow2wTVn NZHOzcbCpcNKRASZm0PotOSoaY186llimTALnUdOn8vK2hqBAELE2/aUdKqhLsW3 iuLmIRRdABqf1RckD4Xz =hnBP -----END PGP SIGNATURE----- --Sig_/pPcHsFceYszgzOj4ExmJMCa--