From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Linear device of two arrays Date: Fri, 21 Jul 2017 08:00:44 +1000 Message-ID: <87d18uydir.fsf@notabene.neil.brown.name> References: <20170705214250.0ea99538@natsu> <595D2ADA.8010907@youngman.org.uk> <5afd5cea-06b8-8524-e4f5-8534f23bd714@hardwarefreak.org> <87van15j9b.fsf@notabene.neil.brown.name> <87o9sn232n.fsf@notabene.neil.brown.name> <1eefd627-1aba-a795-05f0-d2106d3a62a3@gmail.com> <87shhyzhg5.fsf@notabene.neil.brown.name> <38e015fa-a07c-8f1a-3a04-384d973966be@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: <38e015fa-a07c-8f1a-3a04-384d973966be@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Veljko , linux-raid@vger.kernel.org List-Id: linux-raid.ids --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Mon, Jul 17 2017, Veljko wrote: > On 07/15/2017 02:12 AM, NeilBrown wrote: > >> So command should be >> >>>> dd if=3D/dev/md2 of=3DSOMEWHERE/SAFE bs=3D1M skip=3D5626590 >> >> and expect it to create a 3M file. >> >> Use this 'skip' number of the 'seek' number later. >> >> NeilBrown > > Thanks, Neil, now it makes more sense. > > I tried to create new linear device, but mdadm is complaining about=20 > data-offset: > > # mdadm -C /dev/md4 -l linear -n 2 --rounding=3D1M -e 1.0 --data-offset= =3D0=20 > /dev/md2 /dev/md3 > mdadm: invalid data-offset: 0 Bother. mdadm uses "parse_size()" to parse the offset, and this rejects "0", which makes sense for a size, but not for an offset. Just leave the "--data-offset=3D0" out. I checked and that is defintely the default for 1.0. > I noticed that md2 and md3 use 1.2 metadata. Can that be the issue?=20 No the metadata on md4 is quite independent of the metadata on md2 and md3. NeilBrown > > I'm using Debian 8.8 if it makes any difference. > > # mdadm -V > mdadm - v3.3.2 - 21st August 2014 > > What could be the problem? > > Regards, > Veljko > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAllxKA8ACgkQOeye3VZi gbkcZQ/+NdeFqKg9W60/oyOs/7hOARgqrOTa4b3ehqQe1rXxDmwCoqwWQtU5i5Zr aeXKLZ8O2zKzlhPpK77vN+eo+tfGeOJtXjQwlIBGdS61TmceudaWys0QAEIor1p9 jYL2weQDpWGP/ZQcbIrHz5cWDJ1ZMoaSF6pNoya6ITTLrhdv/qx6jmocDec3LvQ+ 6M++gz53ygsIEBlXifYZBGmgL0GSxDmS0I985YVWJDqXtxyCaHaQVWxdBNz2+rKx WJwAiXOkX3pKVT/LLnp/JDMACVrR9scOaMRytxv9XhlKR67VHb2C8iERpjkxPs9g PCITYYsN114DcFpPKd/AIAucPcgKMs7/85gn8+YQB3r474D1VW13neevGiK1ZnsC DhTxP/wvlAT14P0VygddlDS+2AkFznQaeiw/psD8UYSmu+9IrHnMqT3kfyKlUzTe 0xPC+T8xgKWmZSBpmUsZs7rAfSEDRtw1b2jkOMOlzQrYQ1YqXxcuxTLvly4PilSX CZZd+YQyz3a2I2aZFhUXENXXTIIIeRfWxZb+BiK8zvQcLejPvMHp60P8VENTCea/ tO0hSYixmpNvCmZtGfaQgSkoFNM5S+vyXMrrR8rLNgiBUKDGmDbzuTTOW3uwkUPz r+05uervC+LQHzuZXXy7aUQSULpap6eK1K655ekTHkBOT1k5KBI= =ny/M -----END PGP SIGNATURE----- --=-=-=--