From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Szecsei Subject: Re: Confusion with setting up new RAID6 with mdadm Date: Mon, 15 Nov 2010 15:23:13 +0200 Message-ID: <4CE13441.3030504@geograph.co.za> References: <4CE00206.4000301@geograph.co.za> <4CE12741.6070803@geograph.co.za> <4CE12BFB.6050003@ziu.info> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4CE12BFB.6050003@ziu.info> Sender: linux-raid-owner@vger.kernel.org To: Michal Soltys Cc: Mikael Abrahamsson , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 2010-11-15 14:47, Michal Soltys wrote: > On 15.11.2010 13:27, Zoltan Szecsei wrote: >> On 2010-11-14 18:48, Mikael Abrahamsson wrote: >>> >>>> *What is the correct fdisk or parted method get rid of the DOS & G= PT >>>> flags, and create a correctly aligned partition, and should this b= e a >>>> 0xda partiton (& then I use metatdata 1.2 for mdadm)? >>> >>> I just "dd if=3D/dev/zero of=3D/dev/sdX bs=3D1024000 count=3D1" to = zero the >>> first megabyte of the drive to get rid of the partition table (you = get >>> rid of the v1.2 metadata at the same time actually). Then you know = for >>> sure you're correctly aligned as well as md is 4k aligned. >> I did this on all 8 drives (/dev/sd[a-h]) >> root@gs0:/etc# dd if=3D/dev/zero of=3D/dev/sdb bs=3D1024000 count=3D= 1 >> 1+0 records in >> 1+0 records out >> 1024000 bytes (1.0 MB) copied, 0.0103209 s, 99.2 MB/s >> root@gs0:/etc# dd if=3D/dev/zero of=3D/dev/sdc bs=3D1024000 count=3D= 1 >> >> But the GPT id has not disappeared. > > You might want to do blockdev --rereadpt /dev/sd[a-h] to make sure=20 > kernel registers new situation (or do the same with sfdisk -R) > > Also, GPT stores backup partition table + gpt header at the end of th= e=20 > disk. Kernel might be clever enough to rely on it if you destroy the=20 > data at the beginning of the disk. > OK, just done this on all 8 drives: root@gs0:/sys/block# dd if=3D/dev/zero of=3D/dev/sdb bs=3D512 seek=3D39= 07029166 dd: writing `/dev/sdb': No space left on device 3+0 records in 2+0 records out 1024 bytes (1.0 kB) copied, 0.000913281 s, 1.1 MB/s root@gs0:/sys/block# fdisk -lu produces the results below - so presumably the drives now=20 clean & ready for mdadm? BTW: I've just downloaded and compiled the latest mdadm too: root@gs0:/sys/block# mdadm -V mdadm - v3.1.4 - 31st August 2010 root@gs0:/sys/block# Thanks for your (collective) helps... Zoltan root@gs0:/sys/block# fdisk -lu Disk /dev/sda: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sda doesn't contain a valid partition table Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdb doesn't contain a valid partition table Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdc doesn't contain a valid partition table Disk /dev/sdd: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdd doesn't contain a valid partition table Disk /dev/sde: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sde doesn't contain a valid partition table Disk /dev/sdf: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdf doesn't contain a valid partition table Disk /dev/sdg: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdg doesn't contain a valid partition table Disk /dev/sdh: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdh doesn't contain a valid partition table Disk /dev/sdi: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units =3D sectors of 1 * 512 =3D 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e30c7 Device Boot Start End Blocks Id System /dev/sdi1 * 2048 391167 194560 83 Linux Partition 1 does not end on cylinder boundary. /dev/sdi2 393214 976771071 488188929 5 Extended /dev/sdi5 393216 98047999 48827392 83 Linux /dev/sdi6 98050048 110047231 5998592 82 Linux swap / So= laris /dev/sdi7 110049280 976771071 433360896 83 Linux root@gs0:/sys/block# --=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Zoltan Szecsei PrGISc [PGP0031] Geograph (Pty) Ltd. P.O. Box 7, Muizenberg 7950, South Africa. 65 Main Road, Muizenberg 7945 Western Cape, South Africa. 34=B0 6'16.35"S 18=B028'5.62"E Tel: +27-21-7884897 Mobile: +27-83-6004028 =46ax: +27-86-6115323 www.geograph.co.za =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1153 / Virus Database: 424/3257 - Release Date: 11/14/10 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html