Re: How long will this take?

[Michael Stone <mstone@debian.org>]

On Thu, Jun 11, 2020 at 08:52:10PM -0500, David Wright wrote:
> If you were preserving the disk contents (imagine there were
> proprietary encryption software on it), and performed a "read test"
> or ran badblocks on it, would that be sufficient to test the disk's
> performance, as it's merely reading the sectors. Or do you have to
> actually write, with badblocks -r for example?

That really depends on whether you want to test read or write 
performance. If you mean that you want to test for correct operation 
rather than performance then you need a write test to fully exercise the 
disk. Some errors will only be found on write, and conversely some read 
errors will be corrected (remapped) on write.

> The only unaddressed point in my use case is the prevention of a
> high-water mark, because zeroing the drive achieves precisely the
> opposite. What ought I to be running, instead of badblocks -w -t random,
> to achieve that goal?

Create the encrypted volume first, then write zeros to it. :)