What am I doing wrong? Linux seems to be really finicky with LVM compared
to other OS's:

I run this to zero out the first couple of bytes on the disk (i.e. no
partition table info):

dd if=/dev/zero of=/dev/sdb bs=512 count=1

Then I try to pvcreate the whole disk:

/sbin/pvcreate /dev/sdb

and I get the following error:
pvcreate -- device "/dev/sdb" has a partition table

Why's that?! I just zeroed the beginning part of the disk!

fdisk /dev/sdb shows:
Disk /dev/sdb: 64 heads, 32 sectors, 34732 cylinders
Units = cylinders of 2048 * 512 bytes


Any ideas would be appreciated. Please reply to this group. I've had
enough of spammers.

Jack

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In article <Xns92DAAFEBEB432test@204.127.199.17>, Jack Choy wrote:
> dd if=/dev/zero of=/dev/sdb bs=512 count=1
>
> and I get the following error:
> pvcreate -- device "/dev/sdb" has a partition table
>
> Why's that?! I just zeroed the beginning part of the disk!

The bootloader is in the first 512 bytes, the partition table itself is
a bit further on the disk. Why use an over-economical count of 1 when
you can use count=128 and be sure the entire partition table has been
eradicated?

Sybren
-- [colo
r=darkred]
>>> RUNNING A MICROSOFT GAME USING WINE <<<[/color]
sybren@sybren:Mechwarrior Mercenaries$ wine MW4Mercs.exe
INSTR_IDT_Emulate Evil attempt to exploit win9x system security flaws detected
INSTR_IDT_Emulate UNIX system security is too strong, can't emulate properly

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In article <Xns92DB6021C89FDtest@204.127.199.17>, J wrote:
> I tried count=10000 and it still gave me the same results.

Have you tried running fdisk on the disk and removing the partitions by
hand? You never know...

Sybren
-- [colo
r=darkred]
>>> RUNNING A MICROSOFT GAME USING WINE <<<[/color]
sybren@sybren:Mechwarrior Mercenaries$ wine MW4Mercs.exe
INSTR_IDT_Emulate Evil attempt to exploit win9x system security flaws detected
INSTR_IDT_Emulate UNIX system security is too strong, can't emulate properly

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Sybren Stuvel <sybrenUSE@YOURthirdtower.imagination.com> wrote in
news:slrnauvchs.3ci.sybrenUSE@sybren.thirdtower.com:

> In article <Xns92DB6021C89FDtest@204.127.199.17>, J wrote:
>> I tried count=10000 and it still gave me the same results.
>
> Have you tried running fdisk on the disk and removing the partitions by
> hand? You never know...
>
> Sybren

fdisk doesn't see any partition tables. I even did a dd if=/dev/sdb
of=somefile and the file showed all zeroes.

BTW, this is RedHat 8

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In article <Xns92DB8D45B9209test@204.127.202.16>, J wrote:
> fdisk doesn't see any partition tables. I even did a dd if=/dev/sdb
> of=somefile and the file showed all zeroes.

A quick search on google revealed:
http://lists.suse.com/archive/suse-...1-Jun/0280.html

+--------------------------------------------------------------------+
The problem is another one, it took me some fiddling around to find out
what exactly is going on ;-).

Of course a "dd if=/dev/zero of=/dev/sdc bs=1k count=1" destroys the
partition table on the disk. But the kernel does not know about that
command and therefore thinks the partitions that were present on
/dev/sdc before the dd command still exist. pvcreate looks at
/proc/partitions to look for partitions on the disk and in
/proc/partitions the partitions are still present even after the dd
command. So a simple dd command command is not enough to let the kernel
know the partitions on a given disk are gone. The kernel needs to be
informed that he has to re-read the partition table. This is for example
done by the command blockdev --rereadpt <diskname>.
+--------------------------------------------------------------------+

Read the rest of the article and "man blockdev" before continuing ;-)

Sybren
-- [colo
r=darkred]
>>> RUNNING A MICROSOFT GAME USING WINE <<<[/color]
sybren@sybren:Mechwarrior Mercenaries$ wine MW4Mercs.exe
INSTR_IDT_Emulate Evil attempt to exploit win9x system security flaws detected
INSTR_IDT_Emulate UNIX system security is too strong, can't emulate properly

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Thanks for the heads-up. I ended up rebooting the machine instead
to fix that problem. Now things seem to working ok.

Thanx!

Jack

Sybren Stuvel <sybrenUSE@YOURthirdtower.imagination.com> wrote in
news:slrnauvphq.3v7.sybrenUSE@sybren.thirdtower.com:

> In article <Xns92DB8D45B9209test@204.127.202.16>, J wrote:
>> fdisk doesn't see any partition tables. I even did a dd if=/dev/sdb
>> of=somefile and the file showed all zeroes.
>
> A quick search on google revealed:
> http://lists.suse.com/archive/suse-...1-Jun/0280.html
>
> +--------------------------------------------------------------------+
> The problem is another one, it took me some fiddling around to find out
> what exactly is going on ;-).
>
> Of course a "dd if=/dev/zero of=/dev/sdc bs=1k count=1" destroys the
> partition table on the disk. But the kernel does not know about that
> command and therefore thinks the partitions that were present on
> /dev/sdc before the dd command still exist. pvcreate looks at
> /proc/partitions to look for partitions on the disk and in
> /proc/partitions the partitions are still present even after the dd
> command. So a simple dd command command is not enough to let the kernel
> know the partitions on a given disk are gone. The kernel needs to be
> informed that he has to re-read the partition table. This is for
example
> done by the command blockdev --rereadpt <diskname>.
> +--------------------------------------------------------------------+
>
> Read the rest of the article and "man blockdev" before continuing ;-)
>
> Sybren

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In article <Xns92DC986A4DA13test@204.127.199.17>, J wrote:
> Thanks for the heads-up. I ended up rebooting the machine instead
> to fix that problem. Now things seem to working ok.

Good. I hope you've also learned that a quicky on google can help you a
lot ;-)

Sybren
-- [colo
r=darkred]
>>> RUNNING A MICROSOFT GAME USING WINE <<<[/color]
sybren@sybren:Mechwarrior Mercenaries$ wine MW4Mercs.exe
INSTR_IDT_Emulate Evil attempt to exploit win9x system security flaws detected
INSTR_IDT_Emulate UNIX system security is too strong, can't emulate properly

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