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lvm/devfs bug?

linux-lvm Rich Turner 5 participants 12 messages Apr 8, 2003 – Apr 10, 2003

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Rich Turner

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#0 lore raw

i am trying to create a physical volume using the entire disk /dev/sda1 and pvcreate is complaining that there is a partition table on the disk when in fact there isnt.

# pvcreate -ff -v /dev/sda1
pvcreate --device "/dev/sda" has a partition table

i have tried many different things:

# dd if=/dev/zero of=/dev/sda bs=1024 count=10
# blockdev --rereadpt /dev/sda
# sfdisk -R /dev/sda1

i am able to confirm that /proc/partitions does not have a partition entry for the disk but pvcreate still fails. i am using a devfs kernel so i thought there might be some strange behavior between lvm and devfs. is there a fix or known issues regarding lvm and devfs?

#1 lore raw
Quoted 6 lines · Rich Turner

the entire disk /dev/sda1

# pvcreate -ff -v /dev/sda1
pvcreate --device "/dev/sda" has a partition table
# dd if=/dev/zero of=/dev/sda bs=1024 count=10
# blockdev --rereadpt /dev/sda
# sfdisk -R /dev/sda1

Confusion between
/dev/sda and
/dev/sda1 ?

Alasdair

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author
#2 lore raw

sorry, my mistake. i copied it from many different attempt sources. all references should be sda not sda1 because the pv will be located on the entire disk not a partition

Quoted 21 lines · Alasdair G Kergon
Quoted 6 lines · Rich Turner

the entire disk /dev/sda1

# pvcreate -ff -v /dev/sda1
pvcreate --device "/dev/sda" has a partition table
# dd if=/dev/zero of=/dev/sda bs=1024 count=10
# blockdev --rereadpt /dev/sda
# sfdisk -R /dev/sda1

Confusion between
/dev/sda and
/dev/sda1 ?

Alasdair

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[email protected]

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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
#3 lore raw
In reply to Rich Turner
Quoted 5 lines · Rich Turner

i am able to confirm that /proc/partitions does not have a partition entry for the disk but pvcreate still fails. i am using a devfs kernel so i thought there might be some strange behavior between lvm and devfs. is there a fix or known issues regarding lvm and devfs?

if you have devfs you should use the devfs long mane to reference your pv
eg: /dev/scsi/host0/bus0/target0/lun0/disc
as to why the error message is misleading i would not say, lvm1 tools are very buggy wrt the handling of device names.

L.

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Luca Berra -- [email protected]
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author
#4 lore raw

even though devfs is compiled in the kernel it actually is not mounted at this time. i have tried it using devfs long names also with no success.

Quoted 26 lines · Luca Berra
Quoted 5 lines · Rich Turner

i am able to confirm that /proc/partitions does not have a partition entry for the disk but pvcreate still fails. i am using a devfs kernel so i thought there might be some strange behavior between lvm and devfs. is there a fix or known issues regarding lvm and devfs?

if you have devfs you should use the devfs long mane to reference your pv
eg: /dev/scsi/host0/bus0/target0/lun0/disc
as to why the error message is misleading i would not say, lvm1 tools are very buggy wrt the handling of device names.

L.

Signature · 12 lines
Luca Berra -- [email protected]
        Communication Media & Services S.r.l.
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_______________________________________________
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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Signature · 5 lines
Rich Turner
Storix Software
(619)702-6500 phone
(619)702-6501 fax
http://www.storix.com
author
#5 lore raw

its my understanding that pvcreate investigates /proc/partitions for disk information to create the physical volume. if there are no partitions defined on a disk in /proc/partitions then why does pvcreate think there is a partition? am i missing something that pvcreate is looking at to determine disk information?

Quoted 44 lines · Rich Turner

even though devfs is compiled in the kernel it actually is not mounted at this time. i have tried it using devfs long names also with no success.

Quoted 26 lines · Luca Berra
Quoted 5 lines · Rich Turner

i am able to confirm that /proc/partitions does not have a partition entry for the disk but pvcreate still fails. i am using a devfs kernel so i thought there might be some strange behavior between lvm and devfs. is there a fix or known issues regarding lvm and devfs?

if you have devfs you should use the devfs long mane to reference your pv
eg: /dev/scsi/host0/bus0/target0/lun0/disc
as to why the error message is misleading i would not say, lvm1 tools are very buggy wrt the handling of device names.

L.

Signature · 12 lines
Luca Berra -- [email protected]
        Communication Media & Services S.r.l.
 /"\
 \ /     ASCII RIBBON CAMPAIGN
  X        AGAINST HTML MAIL
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_______________________________________________
linux-lvm mailing list
[email protected]
http://lists.sistina.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Signature · 12 lines
Rich Turner
Storix Software
(619)702-6500 phone
(619)702-6501 fax
http://www.storix.com


_______________________________________________
linux-lvm mailing list
[email protected]
http://lists.sistina.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Signature · 5 lines
Rich Turner
Storix Software
(619)702-6500 phone
(619)702-6501 fax
http://www.storix.com
#6 lore raw
In reply to Rich Turner
Quoted 3 lines · Rich Turner

even though devfs is compiled in the kernel it actually is not mounted at this time. i have tried it using devfs long names also with no success.

If devfs is in the kernel you MUST have it mounted for LVM. It's to do with the interaction between /proc/partitions and LVM.

patrick

author
#7 lore raw

i dont completely agree with that because even when i use a kernel that does not have devfs i still get the same symptoms. even though /proc/partitions does not have a partition for a disk pvcreate still complains that there is one. pvcreate must be looking someplace else or there is a bug within lvm.

now, if i create a pv within a partition there are no complaints, lvm will continue normally. it appears to only happen when i want to create a pv on the entire disk.

why does pvcreate think there is a partition when there clearly isnt one?

Quoted 18 lines · Patrick Caulfield
Quoted 3 lines · Rich Turner

even though devfs is compiled in the kernel it actually is not mounted at this time. i have tried it using devfs long names also with no success.

If devfs is in the kernel you MUST have it mounted for LVM. It's to do with the interaction between /proc/partitions and LVM.

patrick

_______________________________________________
linux-lvm mailing list
[email protected]
http://lists.sistina.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

author
#8 lore raw

does anyone recognize this as a bug within lvm?

there clearly is not a partition on sda (according to /proc/partitions) but pvcreate thinks there is one. if pvcreate examines only /proc/partitions for disk partitions and there is not a partition on a disk then why does pvcreate fail? i may not understand all of the underlying behavior of pvcreate but it appears to be failing when it shouldnt. is this a bug?

Quoted 40 lines · rich turner

i dont completely agree with that because even when i use a kernel that does not have devfs i still get the same symptoms. even though /proc/partitions does not have a partition for a disk pvcreate still complains that there is one. pvcreate must be looking someplace else or there is a bug within lvm.

now, if i create a pv within a partition there are no complaints, lvm will continue normally. it appears to only happen when i want to create a pv on the entire disk.

why does pvcreate think there is a partition when there clearly isnt one?

Quoted 10 lines · Patrick Caulfield
Quoted 3 lines · Rich Turner

even though devfs is compiled in the kernel it actually is not mounted at this time. i have tried it using devfs long names also with no success.

If devfs is in the kernel you MUST have it mounted for LVM. It's to do with the interaction between /proc/partitions and LVM.

Quoted 8 lines

patrick

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linux-lvm mailing list
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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

#9 lore raw
Quoted 9 lines · rich turner

does anyone recognize this as a bug within lvm?

there clearly is not a partition on sda (according to /proc/partitions) but pvcreate thinks there is one. if pvcreate examines only /proc/partitions for disk partitions and there is not a partition on a disk then why does pvcreate fail? i may not understand all of the underlying behavior of pvcreate but it appears to be failing when it shouldnt. is this a bug?

If I remember your original message properly, the error you got from pvcreate was that the disk "contained a partition table". This is _not_ the same thing as the disk containing one or more partitions; there can very well be an empty partition table on the disk. This may not be the problem, but if it is, using

dd if=/dev/zero of=/dev/sda count=20

will wipe out any existing DOS-type partition table (or any other type of table that resides at the beginning of the disk). If you've already tried this, then I'd say there is definitely a bug happening.

author
#10 lore raw

i have tried to clear partition table with:

i have tried many different things:

# dd if=/dev/zero of=/dev/sda bs=1024 count=10
# blockdev --rereadpt /dev/sda
# sfdisk -R /dev/sda1

following these commands /proc/partitions does not show a partition on sda but pvcreate complains that there is.

if this is a bug then how do i submit it?

Quoted 29 lines · Kevin P. Fleming
Quoted 9 lines · rich turner

does anyone recognize this as a bug within lvm?

there clearly is not a partition on sda (according to /proc/partitions) but pvcreate thinks there is one. if pvcreate examines only /proc/partitions for disk partitions and there is not a partition on a disk then why does pvcreate fail? i may not understand all of the underlying behavior of pvcreate but it appears to be failing when it shouldnt. is this a bug?

If I remember your original message properly, the error you got from pvcreate was that the disk "contained a partition table". This is _not_ the same thing as the disk containing one or more partitions; there can very well be an empty partition table on the disk. This may not be the problem, but if it is, using

dd if=/dev/zero of=/dev/sda count=20

will wipe out any existing DOS-type partition table (or any other type of table that resides at the beginning of the disk). If you've already tried this, then I'd say there is definitely a bug happening.

_______________________________________________
linux-lvm mailing list
[email protected]
http://lists.sistina.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

#11 lore raw
In reply to rich turner
Quoted 1 line · rich turner

does anyone recognize this as a bug within lvm?

agreed.

there are long standing bugs in the dev scanning code of lvm1, did you try using the devfs name (even if you don't mount devfs you can create the device file manually)
you could also add some more info instead of requoting yourself
eg: contents of the damned /proc/partitions
which version of lvm tools are you running
output of lvmdiskscan
lvmdiskscan -d
pvcreate -d
and so on.

L.

P.S.
please don't post to the list, put it somewhere accessible.

L.

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Luca Berra -- [email protected]
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