A Qnap NAS has a drive with some bad sectors, I want to RMA it, but before just want to figure out how to prepare a drive? It’s part of a raid 5 setup of 4 drives unencrypted. So I want to remove it and wipe it. Got a Linux machine I can use, but never done this before.
What are common Linux tools to do that sensibly?
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I’d recommend /dev/urandom instead of /dev/zero
Use shred , it will automate multiple random passes, and finish with a zero pass.
Completely unnecessary. Overwriting the whole drive with zeros completely stops anyone from being able to recover anything
It won’t stop “anyone”, I’ve been lead to believe there are ways even after a single pass, to recover data. if I had anything to hide, I would use a physical destruction method, nothing else
If you’re that paranoid about it, then just physically destroy the drive.
I work for an it department who resells their old stock online, we scrub the disks before sales, physical destruction is not possible.
That’s the companies decision and they should understand the risks.
This is a miss understanding. Deleting it doesn’t actually delete the data, just the meta data. Overwrite it and it’s gone forever
deleted by creator
sudo dd if=/dev/urandom of=/dev/[sdx] bs=4096K status=progressOr for multiple passes:
sudo shred -fzv /dev/[sdx]Change [sdx] to the drive you want to wipe, make sure you double check it’s the right one.
deleted by creator
Since dipshits are down voting me for being right, I’ll just leave this here
Thank you thats useful to know!
When I sold my drives, I used veracrypt with a 128 character password and PIM of 800+.
Isn’t that the same thing as shredding?
No.
Can you elaborate?
Installing an operating system and enabling encryption won’t overwrite the data on the entire disk. Instead, it will only overwrite on the specific sectors on which this operating system was installed.
Other “previous” data on the disk will remain intact and unaffected.
Unless the OS installer chooses to wipe the driver, which Debian’s (non-calamares) installer does.
I understand what you mean. The way I did it was a full disk encryption as an “external drive” so the whole disk was encrypted
If the drive has bad sectors that it can’t read right now, it likely had other sectors that were marginal and got copied (remapped) to new spare sectors before they became unreadable. So there is still potentially recoverable data in the remapped sectors, and not much you can do about it.
Basically, writing zeros to the disk is about as good as you can hope for. If your data is s00per seekrit to the point where you can’t stand the possibility of any bits at all being recovered, you basically have to melt the drive. Otherwise, zero it and send it in.
Next time, set up encryption ahead of time, so your new drives never see plaintext. Some drives have a “secure erase” feature that is basically a crappy version of this built into the drive.
dd if=/dev/zero of=/dev/(your drive)
You can do status=progress if you want like someone else posted and if you pick a block size go with either the physical block size reported by the disk in smartcontrol or some multiple of it that coincides with a big even division of your controllers memory. The drives physical block size will be “easy” for the drive, bigger blocks are faster.
People saying physical destruction are operating in a different world than you and people saying urandom or shred are operating off old (>30 years) information. The same technology that makes ssds unrecoverable black boxes was originally developed and deployed in spinning drives to eek out speed gains because the disk itself can be expected to know better than the operating system where to put shit and makes techniques (which were postulated but never actually implemented successfully in the wild) to recover overwritten data infeasible.
Alternately just reformat it and don’t worry. No one doing drive rmas cares about your data. They’re already on the razors edge with feedback and customer trust, you think they’re gonna burn their above board bread and butter to run a harvesting operation for a few bucks on the side? That’s usually the purview of your local pc repair shop…
The day job is Private Possum territory, so our agreement is
- we won’t send in drives
- we will send proof of destruction
and I’m sure it costs more, but we don’t have to worry about recovered user data.
Our stuff is also in those crazy-secure datacenters, too, so we don’t need to mess with crypto-at-rest.
