Date: Thu, 9 Feb 2006 13:53:53 -0800 From: "Gayn Winters" <gayn.winters@bristolsystems.com> To: "'Martin McCormick'" <martin@dc.cis.okstate.edu>, <freebsd-questions@freebsd.org> Subject: RE: Using dd to Make a Clone of a Drive Message-ID: <07e501c62dc3$54b3f3f0$6501a8c0@workdog> In-Reply-To: <200602092036.k19KaIhn086956@dc.cis.okstate.edu>
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> [mailto:owner-freebsd-questions@freebsd.org] On Behalf Of > Martin McCormick > Sent: Thursday, February 09, 2006 12:36 PM > To: freebsd-questions@freebsd.org > Subject: Using dd to Make a Clone of a Drive > > > After installing FreeBSD5.4, the ISC dhcp server and ISC bind > on a hard drive, I wanted to clone that drive to a second drive so as > to generate a second server, using what I had already installed as a > template. I used the following command: > > dd if=/dev/da0 of=/dev/da1 bs=512 > > It turns out that dd defaults to 512-byte blocks so I didn't > really need the bs=512, but I am not sure I haven't made some other > type of mistake. The dd command has been running for about 4 hours on > a very fast system, with a 1-gig processor, 1 gig of RAM and two 31-GB > drives. One would think it should have finished by now, but it is > still running. Is this a valid method of copying the entire contents > of one drive to another? Thank you. At this point, let it run. There was a discussion last month on the hackers distribution list on "increasing dd disk to disk transfer rate"; it discussed larger block size, piping (dd if=... | dd of=...), and disk_recover. It is also possible to create your own distribution disk, which may be appealing if you do a lot of cloning. Finally, there is always backup|restore. As for speed, dd will probably be last in a race, especially with large, mostly empty, disks. -gayn Bristol Systems Inc. 714/532-6776 www.bristolsystems.com
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