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From: Julian Elischer <julian@ref.tfs.com>
Message-Id: <199510202317.QAA00924@ref.tfs.com>
Subject: Re: Duplicating whole disks
To: freebsd@fgate.flevel.co.uk (freebsd)
Date: Fri, 20 Oct 1995 16:17:24 -0700 (PDT)
Cc: hackers@FreeBSD.org, graham@flevel.co.uk
In-Reply-To: <Pine.BSF.3.91.951020095901.3976C-100000@fgate.flevel.co.uk> from "freebsd" at Oct 20, 95 10:10:19 am
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the FASTES way (if the TO drive is bigger than the FROM drive)
would be to use the SCSI COPY command using the 
scsi(8) command
(asks one scsi device to read another..)
this would not even utilise the SCSI adapter, let alone the cpu

transfer would be somewhere in the range of the highest speed of
the slower device.

a more standard method (also assuming sizeof(TO) > sizeof(From))
would be 
dd if=FROM of=TO bs=64k

e.g. dd if=/dev/rsd0 of=/dev/rsd1 (or rst0 to send to tape) bs=64k

to do it as a file based copy, I suggest
cd FROM; find . -xdev -depth -print|cpio -pdmuv TO


> 
> 
> 
> Hi
> 
> >From time to time we need to make exact copies of a large number of hard 
> drives partitioned with freebsd.
> 
> The drives are external SCSIs.
> 
> Opinions please on the most efficient and fastest method.
> 
> Would you please Cc: graham@flevel.co.uk
> 
> Thanks v. much
> 
> 
>