From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: Growing 6 HDD RAID5 to 7 HDD RAID5 Date: Tue, 12 Apr 2011 23:14:01 +0600 Message-ID: <20110412231401.5bb9065c@natsu> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/uK_39il30GlX2G6T.fvMYWv"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mathias =?UTF-8?B?QnVyw6lu?= Cc: Linux-RAID List-Id: linux-raid.ids --Sig_/uK_39il30GlX2G6T.fvMYWv Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 12 Apr 2011 17:56:05 +0100 Mathias Bur=C3=A9n wrote: > I'm approaching over 6.5TB of data, and with an array this large I'd > like to migrate to RAID6 for a bit more safety. That's a great decision (and I suppose you made a typo in the subject). RAID5 is downright dangerous at that disk count, and with disks of that siz= e. > I'm just checking if I > understand this correctly, this is how to do it: >=20 > * Add a HDD to the array as a hot spare: > mdadm --manage /dev/md0 --add /dev/sdh1 >=20 > * Migrate the array to RAID6: > mdadm --grow /dev/md0 --raid-devices 7 --level 6 Looks correct to me... The first command can be just "mdadm --add /dev/md0 /dev/sdh1". If you'd rather avoid a reshape at this point, you can add "--layout=3Dpreserve" to the second line. That way you will have just a reb= uild of the new drive, instead of a full reshape. You will also need to "--grow --bitmap=3Dnone" first (you can re-add the bi= tmap later). --=20 With respect, Roman --Sig_/uK_39il30GlX2G6T.fvMYWv Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk2kiFkACgkQTLKSvz+PZwjLGgCfXxmTsFm+jGZ1D/5XmysMq4rN ifkAmgK8Iue40ikcLz+UfFX4ve+Qy9p0 =E1v7 -----END PGP SIGNATURE----- --Sig_/uK_39il30GlX2G6T.fvMYWv--