From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id DDE9B139083 for ; Sat, 9 Dec 2017 16:58:27 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 744B4E10D1; Sat, 9 Dec 2017 16:58:23 +0000 (UTC) Received: from gw2.antarean.org (gw2.antarean.org [141.105.125.208]) by pigeon.gentoo.org (Postfix) with ESMTP id 0CF4BE10A4 for ; Sat, 9 Dec 2017 16:58:22 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gw2.antarean.org (Postfix) with ESMTP id B9C23121BC9 for ; Sat, 9 Dec 2017 17:46:20 +0100 (CET) X-Virus-Scanned: amavisd-new at antarean.org Received: from gw2.antarean.org ([127.0.0.1]) by localhost (gw2.antarean.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id C4wqNZCs3onc for ; Sat, 9 Dec 2017 17:46:20 +0100 (CET) Received: from mailstore1.antarean.org (localhost [127.0.0.1]) by gw2.antarean.org (Postfix) with ESMTP id 1F420121A34 for ; Sat, 9 Dec 2017 17:46:20 +0100 (CET) Received: from eve.localnet (eve.adm.antarean.org [10.55.16.44]) by mailstore1.antarean.org (Postfix) with ESMTP id 9890B32 for ; Sat, 9 Dec 2017 17:58:21 +0100 (CET) From: "J. Roeleveld" To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] OT: btrfs raid 5/6 Date: Sat, 09 Dec 2017 17:58:21 +0100 Message-ID: <1963563.zU3MYjX5FE@eve> Organization: Antarean In-Reply-To: <5A29D35D.1040901@youngman.org.uk> References: <20171207223545.GC18433@tp> <5A29D35D.1040901@youngman.org.uk> 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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" X-Archives-Salt: 813dffab-d9b0-4362-8110-6216d5c2a7ff X-Archives-Hash: 972c2ae2ff99f79beb32e68592e0a08d On Friday, December 8, 2017 12:48:45 AM CET Wols Lists wrote: > On 07/12/17 22:35, Frank Steinmetzger wrote: > >> (Oh - and md raid-5/6 also mix data and parity, so the same holds true > >>=20 > >> > there.) > >=20 > > Ok, wasn=E2=80=99t aware of that. I thought I read in a ZFS article tha= t this were > > a special thing. >=20 > Say you've got a four-drive raid-6, it'll be something like >=20 > data1 data2 parity1 parity2 > data3 parity3 parity4 data4 > parity5 parity6 data5 data6 >=20 > The only thing to watch out for (and zfs is likely the same) if a file > fits inside a single chunk it will be recoverable from a single drive. > And I think chunks can be anything up to 64MB. Except that ZFS doesn't have fixed on-disk-chunk-sizes. (especially if you = use=20 compression) See: https://www.delphix.com/blog/delphix-engineering/zfs-raidz-stripe-width-or-= how-i-learned-stop-worrying-and-love-raidz =2D- Joost