I have a big problem with a partition that is encrypted with luks/dm-crypt. I recognized that some files were not readable any more. I rebooted and the partition was not mountable. As far as I remember there was a non-encrypted partition and behind that the luks/dm-crypt partition (formatted) with ext4 on that harddisk. There was no operating system installed on that harddisk. I was not doing any critical stuff, just working normally, surfing the web etc.
In the gnome-disks utility it shows only "free space" and under "partitioning: unknown (PMBR)". Parted says "Unknown partition table ". fdisk finds a partition: /dev/sdj1 1 4294967295 4294967295 16T ee GPT" which is obviously wrong.
The hard disk is a ST3000DM 001-1CH166 (CC27)
I'm using arch-linux and didn't boot windows for some time.
I now removed the harddisk from the computer and put it into an external usb case, still the same. I am now doing a copy of the harddisk with dd to play around with the image.
What could have possibly gone wrong? Is there a way to recover the data on the encrypted partition?
Update: Luckily I was able to mount the image created with dd:
sudo losetup -Pf data.img
sudo cryptsetup luksOpen /dev/loop0p1 image
sudo mount /dev/mapper/image /mnt
With that I am able to access all the data.