I have a LVM2 Volume Group 'vgXEN' with a Logical Volume in it called 'test-disk'.This is the output of lvdisplay:  --- Logical volume ---LV Path                /dev/vgXEN/test-diskLV Name                test-diskVG Name                vgXENLV UUID                lHSgfx-wnY2-OtRO-zw7l-9SFA-mnht-KgK9MOLV Write Access        read/writeLV Creation host, time DRAKE, 2013-08-26 12:02:08 +0200LV Status              available# open                 0LV Size                10.00 GiBCurrent LE             2560Segments               1Allocation             inheritRead ahead sectors     auto- currently set to     4096Block device           253:4And this is the output of lvscan:ACTIVE            '/dev/vgXEN/test-disk' [10.00 GiB] inheritNow when i try to mount this logical volume with the command i get an error:mount /dev/vgXEN/test-disk /mnt/testmount: you must specify the filesystem typeMy operating system is 'Linux DRAKE 3.2.0-4-amd64 #1 SMP Debian 3.2.41-2+deb7u2 x86_64 GNU/Linux'.Searched the Internet but couldn't find anything useful. Can anybody point me in the right direction please ? Thx !UPDATEThe whole problem is related to storing XEN images and the way i want to backup them (via snapshot / mounting). Below you can read what i did wrong and the way it should be done.What i did wrongI've created 1 logical volume per XEN image, thus storing the disk and swap partition into 1 LV:  LogicalVolume-A  xvda1 (disk)    xvda2 (swap)When you try to mount this LV it tells you 'mount: you must specify the filesystem type' and nothing happens of course. This is because the mount program doesn't know how to read partition tables inside a LV as the people stated in the answers below.The way to do itCreate 1 logical volume per partition, thus storing the disk into 1 LV and the partition into 1 LV:LogicalVolume-A  xvda1 (disk)LogicalVolume-B  xvda2 (swap)  It's now possible to format these logical volumes and use them into your images as storage. Once formatted you are also able to mount them with this simple commandmount /dev/vgXEN/test-disk /mnt/test
Mounting LVM2 volume gives me 'mount: you must specify the filesystem type'
debian;mount;xen;lvm
The Xen image contains probably of one or more partitions and includes therefore a partition table, so you cannot mount it directly.Run file -Ls /dev/vgXEN/test-disk to get information about this.If the output contains something with boot sector and partitions, you can trykpartx -av /dev/vgXEN/test-diskIt creates for each partition a new device in /dev/mapper. You can then either mount this new partitions directly or need to do further steps if there is e.g. a LVM inside the image. It could be there is also a swap partition, which you cannot mount. You can run the file command from above on them to get more information.