From mboxrd@z Thu Jan 1 00:00:00 1970 From: travis+ml-linux-raid@subspacefield.org Subject: SOLVED - Re: md raid0 with overwritten superblock on 1/4 disks Date: Sun, 2 Feb 2014 17:24:05 -0800 Message-ID: <20140203012405.GB7193@subspacefield.org> References: <20140203004137.GA7193@subspacefield.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="TRYliJ5NKNqkz5bu" Return-path: Content-Disposition: inline In-Reply-To: <20140203004137.GA7193@subspacefield.org> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids --TRYliJ5NKNqkz5bu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Funny how the answer is obvious once you ask. I noticed the "Data Offset" was 2048 sectors. On the newly-created md, it was 16 sectors, I think because it was a device mapper overlay and not a real block device. I found this page: http://www.thomas-krenn.com/en/wiki/Linux_Software_RAID Got the mdadm development version that allows setting data offset. 724 parallel truncate -s4000G overlay-{/} ::: $DEVICES 725 parallel 'size=3D$(blockdev --getsize {}); loop=3D$(losetup -f --sho= w -- overlay-{/}); echo 0 $size snapshot {} $loop P 8 | dmsetup create {/}'= ::: $DEVICES 726 cat /proc/mdstat=20 727 mdadm -S /dev/md127 728 ~/src/mdadm-40c9a66/mdadm --create /dev/md127 --data-offset=3D1024= -v -l 0 -n 4 $OVERLAYS That fixed it up (data offset is in k, not sectors). Cheers. --=20 http://www.subspacefield.org/~travis/ Remediating... LIKE A BOSS --TRYliJ5NKNqkz5bu Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (OpenBSD) iQIcBAEBAgAGBQJS7u+1AAoJEGQVZZEDJt9Hpa0P/2qmRqYoJ2NV9eZ08mMjEAHj LzDInbZGW1RdiH1AxjdeYhEun9Cc74/kfMkE3QPkKULeg9vUmU8iMv+IuS9DDpif zp6aSHcbDDqTmCJmO5FL1EHEKpHf0MfOnR3TRdXlVNIBn0Ip0Gn4JM8wAz6B8TlF /gfDV/MPe8hTpBAkT2dTyRgZg9/i8ybjnPyHFihohm70cu0p70VwMQ1H849KxNL0 vZUzaX6zdMa0wif91s0WDElXxqgv2ga1AGcBFaKWdqJe6Ja83cIARdqo1WzUc9Jl Xzpy4JHDFuVg/GqEOoTZCYiNsQCblQc628k3Ylrrf3IwsKCONgPPSxNhtEZMNnqf DbFoaClzdzV12SzdSjdHsuX4Tt4AR9b+BHZdKyblZkfdqkpp8N8buhA+q1rI/hGc X0l+uNY1Lsq64J2hUIiO1rozZb3iDh2/N5LrjpE4qTHIYMfV6ch2NvDEAOzugQVV 5wk94oFgAg6mOJyZcPkPqisMS5/gc7pr/p371dY1IWH2DfbHssA9QCGYOtMG82oR hkZArboDhA5YowYrCriIjpNQzV1rdMFw/td+6SwvVR0BsBtXfb7KQ6XGzqkemRAd xFTQI7fJHmZdkctO8ZPwH3WQUMmpF5axNeLtYFSS09dCQ5dGRzo9rHug/YwvEfGh KvczuKc8T15IhEXhmy00 =TL6B -----END PGP SIGNATURE----- --TRYliJ5NKNqkz5bu--