[rescue] expanding a ZFS pool: leave slack space?

[Peter Corlett]

On Mon, May 03, 2021 at 11:17:28AM -0500, Scott Newell wrote:
[...]
> Here's an example of what I'm concerned about. Two different 32 GB SSDs,
> yet it appears (according to both smartmontools and gdisk) that they don't
> have the same number of sectors!

[...] 
> Device Model:     TS32GMTS600
> Serial Number:    F296620032
> LU WWN Device Id: 5 7c3548 1774ecc00
> Firmware Version: O0918B
> User Capacity:    32,017,047,552 bytes [32.0 GB]

This drive has the exact capacity I would expect from a drive marketed as
32GB as it follows the IDEMA standard. It's a product that's still on the
market, from a reputable brand.

> Device Model:     M2SCF-6M 32GB
> Serial Number:    20171130017109200335
> LU WWN Device Id: 0 000000 000000000
> Firmware Version: Q0707A
> User Capacity:    31,675,383,808 bytes [31.6 GB]

This capacity does *not* follow the IDEMA standard. Normally I would suggest
checking if the capacity had been soft-limited in the Host Protected Area,
however my search for details on that disk came up with that same capacity,
so the disk really is just ~31.6GB. It seems to be about a decade old, from
a no-name Taiwanese vendor. I'd just return it as counterfeit and/or Not As
Described.

I am mildly impressed that you managed to find a disk which does not follow
the IDEMA standard, but then I don't tend to buy storage from the equivalent
of a random bloke in a pub.