[gentoo-user] LVM problems -- mounting a foreign drive

[Daniel Rose]

Hi everyone,

I have an LVM comprising 2 partitions on a drive I wish to read data from, and I have a 'main'
file from somewhere in /etc/lvm from that old drive:


main {
        id = "em7z2K-GhvB-mpW4-YNjE-SiZ7-zia2-PIObh2"

[...]
        physical_volumes {

                pv0 {
                        id = "6oVVgd-WIVK-qB0y-PXk2-Acu5-ZxcI-gMj5JD"
                        device = "/dev/md2"     # Hint only
                        status = ["ALLOCATABLE"]     # 74.4062 Gigabytes
                }
        }

        logical_volumes {
                root {
                        id = "Cu9udo-QFcL-72XW-G1OU-1sQA-giBa-WASzs2"
                        status = ["READ", "WRITE", "VISIBLE"]  # 74.125Gigabytes
                        }
                }

                swap {
                        id = "aM7Jm4-QfMW-4y2c-zCv3-0O6f-CVzz-P3Ebg4"
                        status = ["READ", "WRITE", "VISIBLE"]        #256 Megabytes
  }



some bits snipped, obviously.

Anyway so the lone disk is in a separate box now:

   Device Boot      Start         End      Blocks   Id  System
/dev/hdd1   *           1          13      104391   fd  Linux raid
autodetect
/dev/hdd2              14        9729    78043770   fd  Linux raid
autodetect

So...

 sudo pvcreate -u 6oVVgd-WIVK-qB0y-PXk2-Acu5-ZxcI-gMj5JD /dev/hdd2

Software RAID md superblock detected on /dev/hdd2. Wipe it? [y/n] n
  Physical volume "/dev/hdd2" successfully created

Then....

 pvdisplay
  --- NEW Physical volume ---
  PV Name               /dev/hdd2
  VG Name              
  PV Size               74.43 GB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               6oVVgd-WIVK-qB0y-PXk2-Acu5-ZxcI-gMj5JD



Then....
 sudo vgcreate -v main /dev/hdd2
    Wiping cache of LVM-capable devices
    Adding physical volume '/dev/hdd2' to volume group 'main'
  /dev/hdd2 not identified as an existing physical volume
  Unable to add physical volume '/dev/hdd2' to volume group 'main'.


oh dear.


As it turns out, I can run pvcreate and pvdisplay ok, but a second run
of pvdisplay... and it's gone.  vgcreate always fails.

Any ideas anyone?  I'm a little startled at how hard it seems to be to mount a 'foreign' LVM drive in Linux.




-- 
gentoo-user@g.o mailing list