Since we are unable to access the hardware array then no, the data is lost.
I have not yet worked with BTRFS, but have used LVM for many years. What I hear of BTRFS sounds promising but I have not taken that step yet. That decision is yours once the new raid device is created as you will have to partition and format it for use as any new disk.
Remember, once we start the following set of commands all hope of data recovery is gone, so please be certain before you begin.
I will provide the commands in groups with a brief explanation, so as long as you follow exactly there should be no issue. If there is any point you do not understand or if there is an error it will need to be corrected before trying to continue.
First, in bios switch the sata controller to AHCI instead of raid and reboot so we are working strictly with individual disks. (the screen shot you showed in post #20)
Next we need to remove all raid identification from the drives so the new array can be created from scratch. These commands will need to be run individually and all require sudo or run as root.
Code:
sudo mdadm -S /dev/md127
sudo mdadm /dev/md127 -r /dev/sdd
This should take care of the existing failed md127.
Now we need to erase the raid config from each drive.
This will totally erase your data if there was still any hope
Code:
sudo dd if=/dev/zero of=/dev/sda bs=1M count=1024
sudo dd if=/dev/zero of=/dev/sdb bs=1M count=1024
sudo dd if=/dev/zero of=/dev/sdc bs=1M count=1024
sudo dd if=/dev/zero of=/dev/sdd bs=1M count=1024
At this point if all the above has worked with no errors we need to check if you have an mdadm.conf file and if so remove it.
Code:
sudo rm -f /etc/mdadm/mdadm.conf
Now you should reboot before creating the new raid array.
After the reboot do "cat /proc/mdstat" to verify no traces of the raid remain. This should be empty or no file exists.
Finally we need to create the new array.
I suggest it be named md0 as in the command and this should work. If you choose raid5 or raid6 the only change would be the level number.
Code:
sudo mdadm --create=md0 --raid-devices=4 --level=10 /dev/sda /dev/sdb /dev/sdc /dev/sdd
Once that command completes you should be able to do each of the following and see the status.
Code:
cat /proc/mdstat
sudo mdadm --detail /dev/md0
It may take some time for the array to stabilize and finish assembling so be a little patient
When /proc/mdstat shows something similar to
Code:
$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md127 : active raid6 sdd[3] sde[1] sdc[5] sdb[4]
5766400000 blocks super 1.2 level 6, 512k chunk, algorithm 2 [4/4] [UUUU]
bitmap: 2/22 pages [8KB], 65536KB chunk
unused devices: <none>
then you are ready to use it as a device and can do the partitioning and formatting. At this stage you would set it up with the filesystem you choose, including BTRFS if that is your choice.
Now gparted or similar is the tool needed.
