How do you duplicate a drive?

knowtree at knowtree at
Fri Oct 1 13:07:23 PDT 2004

> I have a RAID mirror (2x 160GB) which I would like to back up onto a spare 
> 160GB drive.
> I do not have a hot-swap caddy so I was planning on powering down the 
> system to get the backup drive in and out.
> But once I have the new blank drive in, what is the best way to duplicate 
> the RAID? Ideally I would like to create a disk that could boot the system 
> (and rebuild the RAID) in case disaster strikes.
> Can dd do this?

As far as I know (never having done it myself) yes, byte for byte.

Before you do that I suggest you read up on vinum, the FreeBSD mirroring
service. There is man vinum, and a lot more in the on-line handbook, and
even more in Greg Lehey's The Complete FreeBSD. Greg wrote vinum, BTW.

(Greg, no charge for the plug.)

Gary Dunn

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