Simulating bad sectors on file based storage device. How?

[Kirk McKusick]

> Date: Tue, 16 Feb 2021 16:05:03 +0300
> From: Artem Kuchin <artem at artem.ru>
> To: Alan Somers <asomers at freebsd.org>
> Cc: freebsd-fs <freebsd-fs at freebsd.org>
> Subject: Re: Simulating bad sectors on file based storage device. How?
> 
>     gnope only allows to set probability, but i need an exact block in an 
>     exact place.

I have a hacked up version of gnop that adds the -F option to tell it
to fail any access to a specific set of sectors. So to make /dev/da0p1
into a disk that failed sectors 64-71, I use

# gnop create -F 64-71 /dev/da0p1

which creates /dev/da0p1.nop with the desired property. No damage
is done to /dev/da0p1 beyond the fact that no writes to the specified
range will be made.

If this driver would be useful, let me know and I'll dig it out.

	Kirk McKusick