I had 2 x 2TB HDDs in a Buffalo CloudStation Pro Duo NAS. Several years ago, I decided that I do not need this NAS anymore and wanted to put them in a disk enclosure to connect the disks via USB. In my stupidness, I clicked on "Remove disk" in the web administration panel, as I thought that this would somehow allow me to mount them when I attach the disks via USB. Well, it turned out that this was not the case (at least for the second disk). I was also not able to remount the disks after I put them in the NAS again.
I do not have this NAS anymore, but the HDDs (cloudshare1 and cloudshare2) and now I finally have the time to try to recover the data.
This NAS supports JBOD, RAID0, and RAID1. Unfortunately, I cannot remember whether I had the disks in a RAID0 array or JBOD. However, I am sure that it was not RAID1, I used the 4TB disk space and the NAS mounted the disks in two separate locations cloudshare1 and cloudshare2.
As already indicated, I tried to attach both HDDs via USB and one disk (cloudshare1) can be mounted but the other disk (cloudshare2) is not mountable (manual recovery via, e.g., UFS explorer works to some extent though).
Strangely, cloudshare1 is mounted as a RAID1 array. Output of mdadm for cloudshare1:
➜ ~ sudo mdadm --examine /dev/sdb6
/dev/sdb6:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : fffdc80a:25d33b5f:0be1a38d:204d070d
Name : UNINSPECT-EM888:21
Creation Time : Tue Dec 20 05:41:32 2011
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 3876622952 (1848.52 GiB 1984.83 GB)
Array Size : 1938311340 (1848.52 GiB 1984.83 GB)
Used Dev Size : 3876622680 (1848.52 GiB 1984.83 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=272 sectors
State : clean
Device UUID : bd313c92:f0e29bd4:de01bfb1:b9fbbbe2
Update Time : Sun Apr 5 13:42:41 2020
Checksum : 3dd971e4 - correct
Events : 317549
Device Role : Active device 0
Array State : A. ('A' == active, '.' == missing, 'R' == replacing)
Here is the /etc/mdadm.conf from the NAS' OS partition:
ARRAY /dev/md127 UUID=3fe75e08:516527a9:c6b301b5:60cfb4cb
ARRAY /dev/md/1 metadata=1.2 UUID=3fff9623:1e04746a:85c2835f:7c463bdb name=UNINSPECT-EM888:1
ARRAY /dev/md/10 metadata=1.2 UUID=bec2d33d:321320a4:f2ecd9b0:9b68692e name=UNINSPECT-EM888:10
ARRAY /dev/md/21 metadata=1.2 UUID=fffdc80a:25d33b5f:0be1a38d:204d070d name=UNINSPECT-EM888:21
Output of fdisk -l when cloudshare1 is attached via USB:
Disk /dev/sdb: 1,84 TiB, 2000398934016 bytes, 3907029168 sectors
Disk model: 3.0
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: E886515F-4153-44FD-9842-7C9A80F94BC3
Device Start End Sectors Size Type
/dev/sdb1 2048 2002943 2000896 977M Microsoft basic data
/dev/sdb2 2002944 12003327 10000384 4,8G Microsoft basic data
/dev/sdb3 12003328 12005375 2048 1M Microsoft basic data
/dev/sdb4 12005376 12007423 2048 1M Microsoft basic data
/dev/sdb5 12007424 14008319 2000896 977M Microsoft basic data
/dev/sdb6 14008320 3890633319 3876625000 1,8T Microsoft basic data
Disk /dev/md127: 976,96 MiB, 1024393216 bytes, 2000768 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/md126: 4,79 GiB, 5119135744 bytes, 9998312 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/md125: 976,101 MiB, 1024446464 bytes, 2000872 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/md124: 1,82 TiB, 1984830812160 bytes, 3876622680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Output of fdisk -l when cloudshare2 is attached via USB:
Disk /dev/sdb: 1,84 TiB, 2000398934016 bytes, 3907029168 sectors
Disk model: 3.0
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Running mdadm on cloudshare2 provides me with this error:
➜ ~ sudo mdadm --examine /dev/sdb
mdadm: No md superblock detected on /dev/sdb.
There appears to be no partition table on this disk and I cannot mount it. However, note that I did not format this disk, yet I am not sure what exactly the "remove disk" action in the web panel did.
I am completely lost. How can I recover data from cloudshare2?