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Re: How long will this take?

On Wed, Jun 10, 2020 at 12:02:13PM -0500, David Wright wrote:
I tried to make clear that my use case differed from that of the OP,
in case you missed that. Just before lockdown (=lockout). I borrowed
an AIO computer and, to make room, returned a 2006 vintage tower that
would no longer pass its POST. I used /dev/zero to erase all the
information from the disk as there was little point in trying to put
Windows XP (licensed to a dead computer) back onto it. Quick, easy,
and quick to check with od. Both l0f4r0 and I have asked why the OP
is zeroing the drive, but no reply yet. Perhaps you can suggest an

I don't really care why the OP is doing it. I can think of several possibilities, but I don't see any need to argue with him over it. At some point it's reasonable to simply accept that someone is trying to do something and either help or not.

My use case for badblocks was closer to that of the OP, but still
different. Firstly, the disk contained personal data from unencrypted
use in the past. Secondly, I was intending to use it encrypted (as
mentioned) and prefer no high-watermark.  Thirdly, because of its
age (2011), I was interested in seeing how well it performed. I have
no idea whether the disk is "modern" in the sense you used, as I don't
follow the technology like some people on this list evidently do.
Fourthly, I don't make a habit of throwing away 2TB disks.

badblocks isn't particularly useful for achieving any of those goals vs just writing zeros. "modern" in this context means anything since probably the mid 90s but my memory is a bit fuzzy on the exact dates. certainly anything since the turn of the century.

But, as you know about these things, a few questions:

. How does badblocks do its job in readonly mode, given that it
 doesn't know what any block's content ought to be.

you have to write the test data ahead of time

. Why might the OP run badblocks, particularly non-destructively
 (as if to preserve something), and *then* zero the drive.

the only person I saw mention badblocks in this thread was you, but I guess I might have missed it

. What's the easiest way of finding out about "consistent bad
 (not remappable) sectors" on a drive, as I soon will have to
 repeat this result (if not by this exact process) with a 3TB
 disk of 2013 vintage. (The good news: it has a USB3 connection.)

you'll get a bunch of errors while writing, and probably the drive will drop offline. you can use smartctl in the smartmontools package to see the status of retries & remapped sectors and get a health report on the drive, which you can use to decide whether to keep the drive in service even if it is currently working. (as a drive ages it will often record an increasing number of correctable errors, which typically will result in failure in the not-distant future.)

a confounding factor is that you might also get write errors and dropped disk if there's a USB issue, separate from whether the drive is working properly. smartctl may help you understand whether there's a physical drive issue, and you can try different USB adapters, ports, and cables.

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