From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:58862 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749AbaCWXL5 (ORCPT ); Sun, 23 Mar 2014 19:11:57 -0400 Date: Sun, 23 Mar 2014 16:11:56 -0700 From: Marc MERLIN To: Hugo Mills , linux-btrfs@vger.kernel.org Subject: Re: Any use for mkfs.btrfs -d raid5 -m raid1 ? Message-ID: <20140323231156.GD18293@merlins.org> References: <20140323224435.GC18293@merlins.org> <20140323225229.GJ25400@carfax.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="gatW/ieO32f1wygP" In-Reply-To: <20140323225229.GJ25400@carfax.org.uk> Sender: linux-btrfs-owner@vger.kernel.org List-ID: --gatW/ieO32f1wygP Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Mar 23, 2014 at 10:52:29PM +0000, Hugo Mills wrote: > On Sun, Mar 23, 2014 at 03:44:35PM -0700, Marc MERLIN wrote: > > If I lose 2 drives on a raid5, -m raid1 should ensure I haven't lost my > > metadate. > > From there, would I indeed have small files that would be stored entire= ly on > > some of the drives that didn't go missing, and therefore I could recover > > some data with 2 missing drives? >=20 > btrfs's RAID-1 is two copies only, so you may well have lost some > of your metadata. n-copies RAID-1 is coming Real Soon Now=E2=84=A2 (Chris= has > it on his todo list, along with fixing all the parity RAID stuff). Oh, right, I forgot about that. Then I'm not coming up with many good reasons why raid1 metadata with raid5 data would be useful. Actually raid5 metadata should be faster since it's striped on more drives. I'll update the doc I just posted, thanks. Marc --=20 "A mouse is a device used to point at the xterm you want to type in" - A.S.= R. Microsoft is to operating systems .... .... what McDonalds is to gourmet coo= king Home page: http://marc.merlins.org/ =20 --gatW/ieO32f1wygP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQCVAwUBUy9qPH4xUKZ2O+kBAQKxfwQA4cFEj89QGE9nIw3UYnle2ADSfNYjWEhG 2baslhJhZJtKyGkgvrzzrNX5h2M6Yb2TQO/8B6QXuZFG6J0gsPFuEAA993oKXgnG Ocn8Y2UAw9jRPy6mcdMU2oWtMRYDfYahxNrrUQS1BSokWJp/xBGtSGiKLniVVd0n yPb9WyZHvbk= =PmNa -----END PGP SIGNATURE----- --gatW/ieO32f1wygP--