FC10 - External USB drive and LVM

[Carl D. Roth]

On Fri, 24 Apr 2009 09:23:11 -0500, Mikkel L. Ellertson wrote:

> Gary Stainburn wrote:
>> Hi folks.
>> 
>> I tried upgrading my FC7 desktop to FC10 which resulted in the PC not
>> booting, crashing during GRUB.
>> 
>> I have now installed FC10 onto a new HDD and want to copy the contents
>> from my old drive to my new one.
>> 
>> I thought that the easiest way would be to use my USB external caddy,
>> but I have a problem.  The box sees the drive, and mounts /boot no
>> problem.
>> 
>> However, I don't have access to the main contents as they were handled
>> by LVM. How can I now acces those filesystems?
>> 

You need to do two things:

1) make sure the VG name on the USB drive is not the same as your new 
system.  If both drives have the same VG name you will have problems.

2) after attaching the USB drive, run

  # pvscan
  # vgchange -a y

Note that LVM isn't usually initialized except at boot time.

If you get stuck by item (1) you can rename the VG using a rescue disk:

  # lvm vgrename OLD NEW

but you still may be hit by item (1) until you disconnect the internal 
hard disk.

C