"This is one of the use cases for the following
procedures (I will describe the process for an intact array and a
degraded array).
"Please note that /dev/md2 is my system partition (mount point
/), so I had to use a rescue system (e.g. Knoppix Live-CD) to
resize the array. If the array you want to resize is not your
system partition, you probably don't need to boot into a rescue
system; but in either case, make sure that the array is
unmounted!"