[CentOS] How to add a HD to a LVM

[Todd Cary]

On 5/8/2011 12:03 AM, Ken Smith wrote:
>
> Todd Cary wrote:
>> I have connected a HD that was a prior system drive (Centos 4.8)
>> and I am not sure of the command line procedures to find out if
>> it is recognized (I believe it is since it present in the GUI),
>> delete all data on it and finally add it to the LVM.
>>
>> I would like to use it as a backup data drive.
>>
>> Todd
>>
>>
> This is an excellent tutorial on LVM.
>
> http://tldp.org/HOWTO/LVM-HOWTO/
>
> Are you planning to join it to an existing Volume Group and then create
> a LV on it for backup? My preference would be to keep things simple and
> to aid recovery in the future, maybe just format the disk ext3 for
> backup. Then it is easy to plug into another box for recovery. But, I'm
> just guessing how you plan to use it.
>
> Ken
>
Ken -

Thank you for your response.  What you suggested is exactly what 
I would like to do: have an extra, stand alone, drive for 
backup.  However, when I do

fdisk -l

I get the output below which has me concerned.  As a "Sunday 
afternoon" user of Centos, I am not 100% sure of my 
interpretation - that is - the drive is already been joined as 
part of the LVM even though all I did was to plug it in as a slave.

My installation of Centos 5.5 is new and I do not remember 
specifying LVM (though that is what I had with my 4.8 system).  
The /dev/hdc (250 GB) is the new system drive.  The /dev/hdd is 
the old Centos 4.8 drive that I would like to have as an 
independent drive e.g. /dev/hda or whatever it needs to be.

What I DO NOT want to happen is for me to accidentally mess up my 
new Centos 5.5 system :-)!!

Questions:

* Is it possible to "remove" /dev/hdd from the LVM - at least it 
appears to be part of it
* Once removed, format it as EXT3 and mount it as /dev/hda (or 
/dev/hdd)

For this I am swimming in unknown waters.

Todd

Disk /dev/hdc: 251.0 GB, 251000193024 bytes
255 heads, 63 sectors/track, 30515 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1          13      104391   83  Linux
/dev/hdc2              14       30515   245007315   8e  Linux LVM

Disk /dev/hdd: 163.9 GB, 163928604672 bytes
255 heads, 63 sectors/track, 19929 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/hdd1   *           1          13      104391   83  Linux
/dev/hdd2              14       19929   159975270   8e  Linux LVM

Disk /dev/sda: 81.9 GB, 81964302336 bytes
255 heads, 63 sectors/track, 9964 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        9964    80035798+   7  HPFS/NTFS


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