# LVM2 unknow filesystem

## nyakimishen

trying to mount a disk from a linux based applience to get some of the base linux files off i recieve this error

```
 

sudo mount sdb2 /mnt/sdb2

mount: unknown filesystem type 'LVM2_member'

```

nothing special about this system

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## alinefr

If it's its LVM you need to:

```

sudo vgscan 

Found volume group "volume_group" using metadata type lvm2

```

Replace "volume_group" with the one from your output:

```

sudo vgchange -ay volume_group

```

You should have one or more logical volumes. You could see then with

```

sudo lvdisplay

```

Now you are able to mount any of those displayed from the last command.

```

sudo mount /dev/mapper/volume_group-vg-name /mnt

```

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## nyakimishen

sudo: vgscan: command not found

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## szatox

You have to take a step back first and try again later. And actually emerge sys-fs/lvm2 in the meantime.

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## NeddySeagoon

nyakimishen,

Logical Volumes are in many ways like partitions.  There is another abstraction layer on top of the physical devices, so that the filesystem knows nothing of the underlying physical devices storing the data.  Its even possible to add and remove physical devices underneath the file system.

This abstraction layer has its own tools collectively called Logical Volume Manager (LVM).  Think of LVM to logical volumes, like fdisk is to disks.

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