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 & GPT
flags, and create a correctly aligned partition, and should this be a
0xda partiton (& then I use metatdata 1.2 for mdadm)?
I just "dd if=/dev/zero of=/dev/sdX bs=1024000 count=1" 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=/dev/zero of=/dev/sdb bs=1024000 count=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=/dev/zero of=/dev/sdc bs=1024000 count=1
But the GPT id has not disappeared.
You might want to do blockdev --rereadpt /dev/sd[a-h] to make sure
kernel registers new situation (or do the same with sfdisk -R)
Also, GPT stores backup partition table + gpt header at the end of the
disk. Kernel might be clever enough to rely on it if you destroy the
data at the beginning of the disk.
OK, just done this on all 8 drives:
root@gs0:/sys/block# dd if=/dev/zero of=/dev/sdb bs=512 seek=3907029166
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
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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 = sectors of 1 * 512 = 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 / Solaris
/dev/sdi7 110049280 976771071 433360896 83 Linux
root@gs0:/sys/block#
--
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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° 6'16.35"S 18°28'5.62"E
Tel: +27-21-7884897 Mobile: +27-83-6004028
Fax: +27-86-6115323 www.geograph.co.za
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