[linux-lvm] Can I dd one disc of a lv

[linux-lvm] Can I dd one disc of a lv

[Tobias Wagener]

Hi,

I have 3 discs, two 180 GB and one 200 GB drive, every drive is
one Partion with a one PV which builds a 560 GB VG from that I 
get a 500 GB LV.

Now the 200 GB hdd is faulty. But I have no change to extend the 
LV, because the Max LV Size is 512 GB. So pvmove isn't possible.
But I have another 200 GB Drive in my system. 

Now the question: Can I "dd" the faulty 200 GB drive to the new 200 GB
drive? And if, how? Does "dd if=/dev/hde1 of=/dev/hdf1" the job, or what
have I to do?


Greetings Tobias

Re: [linux-lvm] Can I dd one disc of a lv

[Rickard Olsson]

Tobias Wagener wrote:

> Now the question: Can I "dd" the faulty 200 GB drive to the new 200 GB
> drive? And if, how? Does "dd if=/dev/hde1 of=/dev/hdf1" the job, or what
> have I to do?

Heinz told me:
"You need to dd starting from the first physical extent (use pvdata -PP 
on the old one and look for pe_on_disk.base) to the same offset on the 
new disk (skip and seek dd option) and you want dd to continue after 
read errors (noerror option)."

Also, I was recently told about the dd_rescue utility, but I haven't had 
the misfortune/opportunity to try that one yet.

    / Rickard Olsson,IT-Konsult/
   / Telefon: +46 70 635 01 42/
  / http://www.webhackande.se/

Re: [linux-lvm] Can I dd one disc of a lv

[Tobias Wagener]

Hi,

OK, currently dd (or better dd_rescue) is at work. What have I to do after 
the dd?

vgexport the VG, and then vgimport with the new device? Or do I use
a "vgcfgrestore" and "vgcfgbackup" also?

Greetings Tobias


On 06/11/03 13:20, Rickard Olsson wrote:
> Tobias Wagener wrote:
> 
> > Now the question: Can I "dd" the faulty 200 GB drive to the new 200 GB
> > drive? And if, how? Does "dd if=/dev/hde1 of=/dev/hdf1" the job, or what
> > have I to do?
> 
> Heinz told me:
> "You need to dd starting from the first physical extent (use pvdata -PP 
> on the old one and look for pe_on_disk.base) to the same offset on the 
> new disk (skip and seek dd option) and you want dd to continue after 
> read errors (noerror option)."
> 
> Also, I was recently told about the dd_rescue utility, but I haven't had 
> the misfortune/opportunity to try that one yet.
> 
>     / Rickard Olsson,IT-Konsult/
>    / Telefon: +46 70 635 01 42/
>   / http://www.webhackande.se/
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Can I dd one disc of a lv

[Rickard Olsson]

Tobias Wagener wrote:

> vgexport the VG, and then vgimport with the new device? Or do I use
> a "vgcfgrestore" and "vgcfgbackup" also?

vgexport/import shouldn't be needed. pvcreate the new disk, 
vgcfgrestore, vgscan and vgchange -ay.

    / Rickard Olsson,IT-Konsult/
   / Telefon: +46 70 635 01 42/
  / http://www.webhackande.se/

Re: [linux-lvm] Can I dd one disc of a lv

[Tobias Wagener]

After I switched the new disc to the "hdX" of the old one? Or in which way
knows the lvm to use the new disc?

On 06/11/03 13:47, Rickard Olsson wrote:
> Tobias Wagener wrote:
> 
> > vgexport the VG, and then vgimport with the new device? Or do I use
> > a "vgcfgrestore" and "vgcfgbackup" also?
> 
> vgexport/import shouldn't be needed. pvcreate the new disk, 
> vgcfgrestore, vgscan and vgchange -ay.
> 
>     / Rickard Olsson,IT-Konsult/
>    / Telefon: +46 70 635 01 42/
>   / http://www.webhackande.se/
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Can I dd one disc of a lv

[Rickard Olsson]

Tobias Wagener wrote:

> After I switched the new disc to the "hdX" of the old one? 

Yes. You can remove the old disk after the dd_rescue is done.

> Or in which way knows the lvm to use the new disc?

I believe vgcfgrestore does that. If you don't want to (or can't) move 
the disks around, check the -o option.

If you want to, you can use the LVM2 pvcreate instead, to create the new 
disk with the PVUUID from the old one. pvdisplay /dev/olddisk tells you 
the ID.

    / Rickard Olsson,IT-Konsult/
   / Telefon: +46 70 635 01 42/
  / http://www.webhackande.se/

Re[2]: [linux-lvm] Can I dd one disc of a lv

[Spam]

> Hi,

> OK, currently dd (or better dd_rescue) is at work. What have I to do after
> the dd?

  Nothing. The drives will be identical to LVM so you should remove
  the faulty drive and then everything should be normal. :) Do not run
  any restore/backup commands.

> vgexport the VG, and then vgimport with the new device? Or do I use
> a "vgcfgrestore" and "vgcfgbackup" also?

> Greetings Tobias


> On 06/11/03 13:20, Rickard Olsson wrote:
>> Tobias Wagener wrote:
>> 
>> > Now the question: Can I "dd" the faulty 200 GB drive to the new 200 GB
>> > drive? And if, how? Does "dd if=/dev/hde1 of=/dev/hdf1" the job, or what
>> > have I to do?
>> 
>> Heinz told me:
>> "You need to dd starting from the first physical extent (use pvdata -PP
>> on the old one and look for pe_on_disk.base) to the same offset on the
>> new disk (skip and seek dd option) and you want dd to continue after
>> read errors (noerror option)."
>> 
>> Also, I was recently told about the dd_rescue utility, but I haven't had
>> the misfortune/opportunity to try that one yet.
>> 
>>     / Rickard Olsson,IT-Konsult/
>>    / Telefon: +46 70 635 01 42/
>>   / http://www.webhackande.se/
>> 
>> 
>> _______________________________________________
>> linux-lvm mailing list
>> linux-lvm@sistina.com
>> http://lists.sistina.com/mailman/listinfo/linux-lvm
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

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

Re: [linux-lvm] Can I dd one disc of a lv

[Spam]

> Hi,

> I have 3 discs, two 180 GB and one 200 GB drive, every drive is
> one Partion with a one PV which builds a 560 GB VG from that I 
> get a 500 GB LV.

> Now the 200 GB hdd is faulty. But I have no change to extend the 
> LV, because the Max LV Size is 512 GB. So pvmove isn't possible.
> But I have another 200 GB Drive in my system. 

> Now the question: Can I "dd" the faulty 200 GB drive to the new 200 GB
> drive? And if, how? Does "dd if=/dev/hde1 of=/dev/hdf1" the job, or what
> have I to do?


  Use dd_rescue instead. That tool is developed to be better than dd
  for copying data off bad drives. dd_rescue can also walk backwards.
  If your system freezes when reaching bad blocks then you can write
  down the block and tell dd_rescue to copy the disk backwards up to
  that block.

> Greetings Tobias



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

RE: [linux-lvm] Can I dd one disc of a lv

[Koch, Steffen]

> I have 3 discs, two 180 GB and one 200 GB drive, every drive 
> is one Partion with a one PV which builds a 560 GB VG from that I 
> get a 500 GB LV.
> 
> Now the 200 GB hdd is faulty. But I have no change to extend the 
> LV, because the Max LV Size is 512 GB. So pvmove isn't 
> possible. But I have another 200 GB Drive in my system. 
> 
> Now the question: Can I "dd" the faulty 200 GB drive to the 
> new 200 GB drive? And if, how? Does "dd if=/dev/hde1 
> of=/dev/hdf1" the job, or what have I to do?
If they are of exact the same size (best would be the same drive) you can do
a "dd if=/dev/hde of=/dev/hdf" and then remove the faulty drive. Should
work.

Greets,
Steffen