advice about copy from disk to disk

Joseph Gleason clash at
Wed May 28 08:04:34 PDT 2003

I usually get better transfer rates with bs=16k or so.

What transfer rate do you get?  If they are modern drives (which 80gb implies) you should get about 20-30MB/s.  At that rate it
should take a little over an hour to transfer.

To see the transfer start the dd, let it run for maybe 10-15 sec and give it a Ctrl+c.  It should print out its transfer rate thus

Probably far more important than block size, is putting those drives on separate ide channels.  Your notation indicates that they
are on the same cable, which will slow it down significantly.  If all of your ide positions are in use, it might be worth while to
get an add on ide card if you are doing this alot.

Also, what ide mode are the drives in?
You can see this with "atacontrol mode N", where N is the number of the ide channel you are intersted in.  If it says PIO4 or
something starting with PIO it will probably be quite slow.

----- Original Message ----- 
From: "adrian kok" <adriankok2000 at>
To: <questions at>
Sent: 28 May, 2003 10:10
Subject: advice about copy from disk to disk

> 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)?
> and is there any tools also
> Thank you very much
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