How to secure erase a Western Digital My Cloud Mirror (Gen 2)?

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Before transmitting a Western My Cloud Mirror 6TB NAS storage in RAID 1 (2x 3 TB) from one customer (selling it) to another one (buying it), I need to wipe the data, whilst preserving intact the system features.

In the NAS, the drives were in RAID 1. I extracted them from their enclosure and connected them in SATA using.

Listing the drives with fdisk -l in Linux Parted Magic distro gives the output below. The volume with the data is obviously dev/md1.

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sda: 3000.6 GB, 3000592982016 bytes
256 heads, 63 sectors/track, 363376 cylinders, total 5860533168 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 identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1  4294967295  2147483647+  ee  GPT
Partition 1 does not start on physical sector boundary.

WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes
256 heads, 63 sectors/track, 363376 cylinders, total 5860533168 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 identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1  4294967295  2147483647+  ee  GPT
Partition 1 does not start on physical sector boundary.

Disk /dev/md0: 2147 MB, 2147418112 bytes
2 heads, 4 sectors/track, 524272 cylinders, total 4194176 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/md1: 2996.3 GB, 2996296343552 bytes
2 heads, 4 sectors/track, 731517662 cylinders, total 5852141296 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

So, my questions:

  1. To wipe the data stored on /dev/sda and /dev/sdb drives, will it suffice to shred dev/md1?
  2. After applying shred, will I have to reformat the "volumes" making dev/md1 RAID? I don't think so as the data area on each drive show as RAW, but I would like to be sure before wiping the drive.
  3. After data deletion mentioned at points 1 and 2, will the 40-seconds reset suffice to restore the WD My Cloud Mirror to factory state and prevent the new user from accessing the data from a previous user?

If the data were synced with some remote account in the cloud, I want to make sure that the buyer cannot accidentally access the seller's files there.

Thanks.

raid-1
secure-erase
asked on Super User Oct 10, 2018 by OuzoPower

1 Answer

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  1. Using shred with one pass would be enough

    shred -v -n 1 /dev/sda

  2. No need to reformat as shred will remove all data including its format and partition tables.

  3. You can unmount the drive partitions by umount /dev/sda1 or umount /dev/sdb1. Also removing it from /etc/fstab.

answered on Super User Oct 11, 2018 by sudo

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