HDD-manufacture induced ZFS limitations

[Zenny]

Hi:

PROBLEM

I came across a very weird situation because HDD-manufacturer counts
HDD space according to metric system instead of multiplication of 1024
(2^10). This mismatches the space capacity between what OS filesystems
calculate HDD space.

Secondly, each HDD manufacturer has different total byte size for what
they claim as the same sized HDDs.

With the above two scenarios, it poses a nuisance to replace a
corrupted HDD with another HDD from another manufacturer even though
they claim that they are of the equal size, but differs by a few
bytes. Thus, zfs does not accept the new HDD.

SOLUTION

A way around is to create a sparse zfs dataset at the beginning,
according to the HDD-manufacturer defined metric system of HDD space
measurement at the power of 10 rather than 2^10.

BUT ANOTHER PROBLEM
However, I came across another odd situation with  the bsdinstaller
with FreeBSD 10-Beta2 which has an option to install root in zfs. The
bsdinstaller script is flawless as it is. But it does not address the
disksize mismatch problem as stated above. Any workaround will be
appreciated!

It would be a nice feature if the new bsdinstaller in FreeBSD10 allows
the user first to make a sparse zfs dataset before installing root in
zfs. Thanks!

/z