From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.g1.pair.com ([66.39.3.162]:41549 "EHLO mail1.g1.pair.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935043AbeAORIX (ORCPT ); Mon, 15 Jan 2018 12:08:23 -0500 Date: Mon, 15 Jan 2018 18:08:26 +0100 From: Emmanuel Florac Subject: Re: Growing RAID10 with active XFS filesystem Message-ID: <20180115180826.01665812@harpe.intellique.com> In-Reply-To: <37abf496-57aa-fd12-26b7-09d43f08e6d5@youngman.org.uk> References: <20180108192607.GS5602@magnolia> <20180108220139.GB16421@dastard> <5A548D31.4000002@youngman.org.uk> <20180109222523.GJ16421@dastard> <85f60b96-b2ca-be84-a7f6-380b545c3ac8@turmel.org> <20180111030723.GU16421@dastard> <5A58B901.7080609@youngman.org.uk> <20180112152538.2c4d8cd4@harpe.intellique.com> <37abf496-57aa-fd12-26b7-09d43f08e6d5@youngman.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/cGC7Lu0slVysKYXb2rcXYKI"; protocol="application/pgp-signature" Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Wol's lists Cc: Dave Chinner , linux-xfs@vger.kernel.org, linux-raid@vger.kernel.org --Sig_/cGC7Lu0slVysKYXb2rcXYKI Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Le Sun, 14 Jan 2018 21:33:17 +0000 "Wol's lists" =C3=A9crivait: > On 12/01/18 14:25, Emmanuel Florac wrote: > >> My point is that all this causes geometries to change, and ext and > >> btrfs amongst others can clearly handle this. Can XFS? =20 >=20 > > Neither XFS, ext4 or btrfs can handle this. That's why Dave > > mentioned the fact that growing your RAID is almost always the > > wrong solution. A much better solution is to add a new array and > > use LVM to aggregate it with the existing ones. =20 >=20 > Does the new array need the same geometry as the old one? That's the best way to preserve performance, yes. =20 > What happens if my original array is a 4-disk raid-5, and then I add > a 3-disk raid-5? Can XFS cope with the different optimisations > required for the different layouts on the different arrays? No because your array will remain optimised for the initial layout. However, if you add a new array with the same stripe characteristics you should at least NOT lose performance. See also the mount options Stan mentioned earlier :) --=20 ------------------------------------------------------------------------ Emmanuel Florac | Direction technique | Intellique | | +33 1 78 94 84 02 ------------------------------------------------------------------------ --Sig_/cGC7Lu0slVysKYXb2rcXYKI Content-Type: application/pgp-signature Content-Description: Signature digitale OpenPGP -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlpc4AoACgkQX3jQXNUicVanHgCg43/NQQ0c8KsZWZWDxtSHf6oP wUAAoJy932P8g04MufkNxCjZIhI8RAbw =B8gg -----END PGP SIGNATURE----- --Sig_/cGC7Lu0slVysKYXb2rcXYKI--