2007
05.07

i foobar’d a fedora 4 machine a couple of days ago and when i went to mount the disk into another machine i get this beautiful error:

mount: unknown filesystem type 'LVM2_member'

here was the syntax used:

termcb:~ # mount /dev/hda2 /mnt/old/
mount: unknown filesystem type 'LVM2_member'

and here was the drive :

termcb:~ # fdisk -l

Disk /dev/hda: 30.0 GB, 30005821440 bytes
255 heads, 63 sectors/track, 3648 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 13 104391 83 Linux
/dev/hda2 14 3648 29198137+ 8e Linux LVM

so using lvm2 tools, we do a disk scan:

termcb:~ # lvmdiskscan
/dev/ram0 [ 62.50 MB]
/dev/ram1 [ 62.50 MB]
/dev/hda1 [ 101.94 MB]
/dev/sda1 [ 39.19 MB]
/dev/ram2 [ 62.50 MB]
/dev/hda2 [ 27.85 GB] LVM physical volume
/dev/sda2 [ 2.01 GB]
/dev/ram3 [ 62.50 MB]
/dev/sda3 [ 60.00 GB]
/dev/ram4 [ 62.50 MB]
/dev/sda4 [ 86.96 GB]
/dev/ram5 [ 62.50 MB]
/dev/ram6 [ 62.50 MB]
/dev/ram7 [ 62.50 MB]
/dev/ram8 [ 62.50 MB]
/dev/ram9 [ 62.50 MB]
/dev/ram10 [ 62.50 MB]
/dev/ram11 [ 62.50 MB]
/dev/ram12 [ 62.50 MB]
/dev/ram13 [ 62.50 MB]
/dev/ram14 [ 62.50 MB]
/dev/ram15 [ 62.50 MB]
0 disks
21 partitions
0 LVM physical volume whole disks
1 LVM physical volume

then we do a lvdisplay so we can get the LV Name and VG Name:

termcb:~ # lvdisplay
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID WBjpH6-Jezl-aI1z-XVSp-WzvW-qTDi-c1jkUv
LV Write Access read/write
LV Status NOT available
LV Size 26.06 GB
Current LE 834
Segments 1
Allocation inherit
Read ahead sectors 0

--- Logical volume ---
LV Name /dev/VolGroup00/LogVol01
VG Name VolGroup00
LV UUID Zykaw3-WBHU-oink-38W9-KylN-7u5j-PKx8qT
LV Write Access read/write
LV Status NOT available
LV Size 1.75 GB
Current LE 56
Segments 1
Allocation inherit
Read ahead sectors 0

and also a vgdisplay to make sure it was the right drive:

termcb:~ # vgdisplay
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 27.84 GB
PE Size 32.00 MB
Total PE 891
Alloc PE / Size 890 / 27.81 GB
Free PE / Size 1 / 32.00 MB
VG UUID ryYRi4-mXOd-XFaW-4xnR-h1cl-hphh-5QQnlM

so at this point i re-tried to mount but using the VG Name:

termcb:~ # mount /dev/VolGroup00/LogVol00 /mnt/old/
mount: special device /dev/VolGroup00/LogVol00 does not exist

still failure

so i did an lvscan next to see what the status of the lv drive is:

termcb:~ # lvscan
inactive '/dev/VolGroup00/LogVol00' [26.06 GB] inherit
inactive '/dev/VolGroup00/LogVol01' [1.75 GB] inherit

fuck…. still inactive
thats when i stumbled across this post :
http://www.fedoraforum.org/forum/archiv … 64964.html

now the rest was pretty self explanatory:

modprobe dm-mod

vgchange -ay

termcb:~ # lvscan
ACTIVE '/dev/VolGroup00/LogVol00' [26.06 GB] inherit
ACTIVE '/dev/VolGroup00/LogVol01' [1.75 GB] inherit

mount /dev/VolGroup00/LogVol00 /mount/point

Success!!

this was done on a suse 10.1 box trying to mount a fedora 4 drive.

if this was gentoo it probably would have been much easier.

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charlie root

VP of keeping it real / HNIC at pissedoffadmins.com
I bring the cold coffee.

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133 comments so far

Add Your Comment
  1. Thanks for sharing this. Way to go

  2. That was a great help. Thank you. I like the way you ran through the stages. I have mounted and am just getting into the home directory with ecrypt-recover-private using ecrypt-utils.

  3. thank your. really helpful. saved me too.

  4. you are my hero!!!! tnks!!!

  5. Very very help full.. thanks dud!!

  6. Perfect!!! Thanks so much, saved me too :)

  7. Bravo! Saved me a lot of hair pulling

  8. Thank you very much for this post! It saved me from pulling out my hair. :)

  9. dude you are a god

  10. Helpful and precise. Easy to follow too.
    Great guide.

  11. Thank you bro! You save my life (:

  12. I tried mount using volume group and logical volume (active), and its showing
    “mount: you must specify the filesystem type”

    Can you help me out

  13. Thank you! Worked great

  14. same scenario – you saved me!

  15. Thank you very much for your post. Followed your steps, and thought I had my own problem solved, but then I got one complication further. I posted my question on StackExchange:

    https://unix.stackexchange.com/questions/282591/mount-unrecognised-segment-type-thin

    If you know any badass system administrators willing to help with this problem, maybe you can let them know.

  16. Thanks :) I was facing same issue, it helped me.Thanks

  17. Thank you! Worked with a disk with Ubuntu 14.04 installed.

  18. LVM is active now. but when i try to mount it , it says

    mount: you must specify the filesystem type

  19. Very helpful….thankyou

  20. you did it!

  21. Thanksyou so much

  22. Thank you! saved me tons of time

  23. thanks solution, finally saved my data

  24. Very nice.
    Helpfull, this article helps me to access my LVM.

  25. Thank you!!!! You saved my life!:-)