> Yeah but from memory I think the LVM tools operate in powers of two

So let me quote the lvs manpage now:

>       --units hHbBsSkKmMgGtTpPeE
>              All sizes are output in these units: (h)uman-readable, (b)ytes, (s)ectors, (k)ilobytes, (m)egabytes, (g)igabytes, (t)erabytes, (p)etabytes, (e)xabytes.  Capitalise to use  multiples  of  1000
 >             (S.I.) instead of 1024.  Can also specify custom units e.g. --units 3M

And we're using a capital G, ie the SI version.

> Also, I think megabytes (or mebibytes) would be better than gigabytes (or gibibytes) since
> 
> a) in a virtualized dev/test environment, a DB <1GB can be sufficient
> b) customers may want to avoid rounding to the nearest gigabyte.

I pretty much doubt anyone really cares about +/- something of less than 1GB. Even in a virtualized setup.