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I'm attempting to recover (what I'm told is) a btrfs partition from a RAID5 array and I'm a bit stuck on the next step...

The reason I mention it was RAID5 is because the array way deleted in the controller software (!). I was able to recreate without reinitialising and reboot from a recovery CD and I can see all the original partitions:

>fdisk -l

Disk /dev/sda: 7.3 TiB, 8000450330624 bytes, 15625879552 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 65536 bytes / 131072 bytes
Disklabel type: gpt
Disk identifier: 5ED632A8-C1B1-437B-89B5-A05C6312E1C4

Device           Start         End     Sectors  Size Type
/dev/sda1         2048     1026047     1024000  500M EFI System
/dev/sda2      1026048     1288191      262144  128M Microsoft reserved
/dev/sda3      1288192   206088191   204800000 97.7G Microsoft basic data
/dev/sda4  15624953856 15625875455      921600  450M Windows recovery environment
/dev/sda5    206088192 15624953855 15418865664  7.2T Linux filesystem

I thought that was a good sign, unfortunately I'm not able to mount the partition:

mount: /mnt/test: wrong fs type, bad option, bad superblock on /dev/sda5, missing codepage or helper program, or other error.

and a btrfs check says 'no valid Btrfs found on /dev/sda5'.

Is this a lost cause? Just some pointers on the next steps to try would be really appreciated.

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  • Interesting problem. I have several questions. Do you have access to the other RAID5 devices? "the array way deleted in the controller software" ... Which controller SW? – rickhg12hs Feb 22 '20 at 19:35
  • I can mount and read from the 'EFI' partition (/dev/sda1), but all the other partitions are giving the same problems, although it's not clear what file system they were using (FAT/NTFS, I assume - this is a Dell Precision tower that shipped with Win10 and was rebuilt with Manjaro by an ex-colleague). It was deleted in the RAID controller software on boot up by someone who didn't know what they were doing! I just recreated and booted up hoping it would stil be available... – 16shells Feb 23 '20 at 18:31
  • A RAID5 needs at least 3 devices to make any sense. Where are they? Looking at the RAID deletion instructions in Dell's Workstation RAID manual, there are multiple RAID controller possibilities but they seem to claim the data is deleted when the RAID is deleted. Depending on how the RAID controller striped the RAID5 data/parity across the devices, it might be easy or impossible to recover data from a single device. – rickhg12hs Feb 23 '20 at 23:13
  • Thanks for the input @rickhg12hs, but the view above is the virtual drive from the recovery os. I've rebuilt the array already from the raid controller s/w and that bits fine - I only mention it as likely reason/background for why the partition/s have become corrupt. – 16shells Feb 24 '20 at 12:27
  • Ahhh, it wasn't clear to me that /dev/sda5 was the rebuilt RAID. I wonder if TestDisk can provide any useful analysis or partial recovery. – rickhg12hs Feb 24 '20 at 15:53

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