I was trying to mount one of the disks from a failed RAID array. The disk was put in a USB enclosure and hooked to the machine. Here’s what I saw:
srv0:~# mount /dev/sdc3 /mnt/usb/
mount: unknown filesystem type 'mdraid'
srv0:~# mdadm --examine /dev/sdc
mdadm: No md superblock detected on /dev/sdc.
I panicked a little, then tried the following that worked:
srv0:~# mount /dev/sdc3 /mnt/usb/ -o ro -t ext3
srv0:~# ls /mnt/usb
bin dev etc initrd.img lib64 media opt root selinux sys usr vmlinuz
boot home lib lost+found mnt proc sbin srv tmp var