[Discuss] Raid 5 Disk Won't Rebuild

[bogstad at pobox.com (Bill Bogstad)]

On Sun, Jan 15, 2012 at 10:19 PM, Edward Ned Harvey <blu at nedharvey.com> wrote:

>> What's the best utility to back up the whole disk, allowing me to restore
>> to a drive (or array) of a different size? ?I had considered DD, but I
>> don't think I can restore the image if the disk sizes don't match, am I
>> wrong?
>
> dd would certainly be easy - but it will waste all sorts of disk space on
> the backup destination, and it simply won't work if you try to restore onto
> a new device of a different size.

I agree with your statement about dd potentially wasting space (and
time).  However, if you are careful to copy to a new disk (or
partition) that is at least as big as the original it can be made to
work.   In the old days, you might have to do something to force the
system to use the correct (fake) geometry to access the data; but most
OSes just use linear block addressing now anyway so this is less
likely to be a problem.  It's certainly worth trying if you are in a
disaster recovery situation.

Bill Bogstad