advice about copy from disk to disk
scott+freebsd at fishballoon.org
Wed May 28 07:39:53 PDT 2003
On Wed, May 28, 2003 at 10:10:19PM +0800, adrian kok wrote:
> Hi all
> Can you give me advice: quicky copy from disk to disk
> I use command dd and it almost takes the whole day to
> copy 80G data!
> dd if=seondary master of=secondary slave bs=1024
> (Secondary master to secondary slave)?
1. Use a much larger block size. I think 64k or 128k will be about as good
as you can get, but you probably want to experiment to see what works
best on your system.
2. Put the drives on separate cables if possible. Most ATA drives are
pretty dumb - I imagine your are hogging the bus so that you can't read
and write simultaneously.
3. Make sure you have DMA turned on if the drives support it (man
atacontrol) and that you're using 80-wire cables if your drives and
controller can run at UDMA66 speed or faster.
Hope that helps,
Scott Mitchell | PGP Key ID | "Eagles may soar, but weasels
Cambridge, England | 0x54B171B9 | don't get sucked into jet engines"
scott at fishballoon.org | 0xAA775B8B | -- Anon
More information about the freebsd-questions