Hello friends!
Today I have a problem with mounting the filesystem:

# mount /dev/mapper/fujitsu_test /u01
mount: you must specify the filesystem type
# mount -t ext4 /dev/mapper/fujitsu_test /u01
mount: wrong fs type, bad option, bad superblock on /dev/mapper/fujitsu_test,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so

Can anybody help me?

Maybe it's not ext4 - unless you're sure of that try some other formats.

Maybe to obvious but is fujitsu_test already formatted to a specific FS?

This filesystem was workable earlier. (It is my test system, on production system same filesystem mounted as ext4, so I decided that test filesystem is ext4 too.)

I founded something:
# ls -l /dev/disk/by-id|grep -i #my_uuid#
lrwxrwxrwx. 1 root root 10 Nov 1 16:18 dm-uuid-mpath-#my_uuid# -> ../../dm-2
lrwxrwxrwx. 1 root root 9 Nov 6 14:23 scsi-#my_uuid# -> ../../sdh
lrwxrwxrwx. 1 root root 9 Nov 6 14:23 wwn-0x#my_uuid# -> ../../sdh

# mount -t ext4 /dev/dm-2 /u01
mount: wrong fs type, bad option, bad superblock on /dev/mapper/fujitsu_test,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
# mount -t ext4 /dev/sdh /u01
mount: /dev/sdh already mounted or /u01 busy

# fuser -c /dev/sdh
/dev/sdh: 2336
# ps -ef | grep 2336
root 2336 1 0 Nov01 ? 00:00:44 /sbin/multipathd

what is it?

Is it a raid or LVM partition? What do you mean by same filesystem on production system? Is it a cloned partition?

It's not clone, but long time ago two servers were created similarry.
This disk is not in lvm.

Please post the following commands' output (Run as root)

# dmsetup -l
dmsetup: invalid option -- 'l'
Couldn't process command line.
# fdisk -l

Disk /dev/sda: 146.8 GB, 146778685440 bytes
255 heads, 63 sectors/track, 17844 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00048103

Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 17845 142825472 8e Linux LVM

Disk /dev/sdb: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdd doesn't contain a valid partition table

Disk /dev/sde: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sde doesn't contain a valid partition table

Disk /dev/sdf: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdf doesn't contain a valid partition table

Disk /dev/sdg: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdg doesn't contain a valid partition table

Disk /dev/sdh: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdh doesn't contain a valid partition table

Disk /dev/sdi: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdi doesn't contain a valid partition table

Disk /dev/mapper/vg_test-lv_root: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_test-lv_root doesn't contain a valid partition table

Disk /dev/mapper/vg_tets-lv_swap: 36.0 GB, 35953573888 bytes
255 heads, 63 sectors/track, 4371 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_test-lv_swap doesn't contain a valid partition table

Disk /dev/mapper/fujitsu_test: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/fujitsu_test doesn't contain a valid partition table

Disk /dev/mapper/fujitsu_back: 3298.5 GB, 3298534883328 bytes
255 heads, 63 sectors/track, 401024 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/fujitsu_back doesn't contain a valid partition table

Disk /dev/mapper/vg_oracle_backup-lv_backup: 3298.5 GB, 3298530689024 bytes
255 heads, 63 sectors/track, 401023 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_oracle_backup-lv_backup doesn't contain a valid partition table

Disk /dev/mapper/vg_test-lv_home: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_test-lv_home doesn't contain a valid partition table

Disk /dev/mapper/vg_test-lv_oracle: 83.5 GB, 83454066688 bytes
255 heads, 63 sectors/track, 10146 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_test-lv_oracle doesn't contain a valid partition table

Disk /dev/mapper/vg_test-lv_tmp: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/vg_test-lv_tmp doesn't contain a valid partition table

The disk is either empty or dead.

p.s. by empty I mean completely unformatted

It is so sadly!

@applehalf: Are you sure /dev/mapper/fujitsu_test isn't part of LVM/Raid?

What does pvdisplay show?

Also, what is the output of ls -l /dev/mapper/ and dmsetup ls

# pvdisplay
--- Physical volume ---
PV Name /dev/mapper/fujitsu_back
VG Name vg_oracle_backup
PV Size 3.00 TiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 786431
Free PE 0
Allocated PE 786431
PV UUID ***************

--- Physical volume ---
PV Name /dev/sda2
VG Name vg_test
PV Size 136.21 GiB / not usable 2.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 34869
Free PE 0
Allocated PE 34869
PV UUID ***************

# ls -l /dev/mapper
total 0
crw-rw----. 1 root root 10, 62 Nov 1 16:18 control
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 fujitsu_back -> ../dm-3
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 fujitsu_test -> ../dm-2
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_test-lv_home -> ../dm-5
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_test-lv_oracle -> ../dm-6
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_test-lv_root -> ../dm-0
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_test-lv_swap -> ../dm-1
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_test-lv_tmp -> ../dm-7
lrwxrwxrwx. 1 root root 7 Nov 1 16:18 vg_oracle_backup-lv_backup -> ../dm-4
# dmsetup ls
vg_test-lv_home (253, 5)
vg_test-lv_swap (253, 1)
vg_test-lv_root (253, 0)
fujitsu_back (253, 3)
vg_oracle_backup-lv_backup (253, 4)
vg_test-lv_tmp (253, 7)
vg_test-lv_oracle (253, 6)
fujitsu_test (253, 2)

It seems that /dev/mapper/fujitsu_test has been part of LVM/Raid (or it is, but not set-up/implemented correctly):

lrwxrwxrwx. 1 root root 7 Nov 1 16:18 fujitsu_test -> ../dm-2
fujitsu_test (253, 2)

However, I'm not sure how this happened or how to restore it to the original setup.

OK, than the right way will be to format my disk and create new volume group.
Thank you.