dd - cloning a disk.

[Mike Jeays]

On Sun, 2006-03-12 at 16:53 +0300, Andrew Pantyukhin wrote:
> On 3/12/06, Wojciech Puchar <wojtek at tensor.3miasto.net> wrote:
> > >
> > > It is, with a few 'buts'. Firstly, the source should be mounted
> >
> > but may not - unless system is generally idle. fsck will be checking the
> > copy then, but with success.
> 
> No matter what fsck says later, it's too dangerous. A FreeBSD
> system (as well as any other complicated OS) is never really
> idle in terms of disk I/O.
> 
> 
> On 3/12/06, Wojciech Puchar <wojtek at tensor.3miasto.net> wrote:
> > > list sometime in the last 3-5 weeks.  Giorgios Keramidas
> > > commented that "dd" was too slow for his tastes and
> >
> > dd is the fastest, but probably he used small block size. 64K is OK
> 
> dd can be slower than dump/restore in quite a few cases,
> especially when disk is far from full.
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I have done this 'safely', by booting Knoppix, and using dd to copy the
disk in the knowledge that all the UFS filesystems are closed and clean.
Use a large blocksize; you can go a lot bigger than 64K.
-- 
Mike Jeays
http://ca.geocities.com/mike.jeays@rogers.com