Comment 3 for bug 1513085

It's fine by me if the finest granularity we allow is 4MB and also fine
if we waste up to that amount at the start of any disk that MAAS
touches. Seriously, disks are cheap these days :)

So let's just round off to the nearest 4MB and optimise for clean
performance rather than squeezing every byte off the disk. All SSDs are
overprovisioned anyhow, the actual size of the disk bears no correlation
to these numbers!

I'd absolutely NOT want the admin to be thinking about sectors AT ALL.
Just let them specify sizes down to the nearest 4MB and we'll be fine.
Let parted handle the actual micro-layout. If using "1 compact unit" is
the best way to be optimised at the start, let's do that. And to be
safe, feed it the end of the final partition as "-1" in compact units
rather than running the risk that it fails due to a small block count issue.

Mark