Re: dd to clone a drive
- Date: Tue, 26 Sep 2017 10:17:32 -0400
- From: Michael Stone <mstone@xxxxxxxxxx>
- Subject: Re: dd to clone a drive
On Tue, Sep 26, 2017 at 09:57:57AM -0400, Jack Dangler wrote:
I have an existing drive near EOL (judging from the sounds). I got a
replacement drive for it (same size).
I plugged the replacement into a USB port and started a byte-for-byte
dd if=/dev/sda of=/dev/sdc
The process ran quietly for almost 30 hours with no discernable
results so i killed it. Apparently, it had been running the whole time
and resulted in approximately 300 of 500Gb copied. Is it 'usual' to
have dd take upwards of 2 days to copy a drive ?
The source drive is a 500G 5400rpm WD, and the target is a 500G
7200rpm WD black.
Try adding bs=64k to the command line. Your current version copies 512
bytes at a time, which is painfully slow. If both drives are USB and on
the same bus, that's going to be another source of performance issues.
With USB2 you'll get about 20MByte/s if both are on the same bus, and
about 40MByte/s if there's just one. (You can see what bus you're
attached to with with "lsusb", and you can use "lsusb -t" to see the
speed the device is currently using in megabits per second. If you have
other busses available you can try changing ports.)
Also, you can send dd the USR1 signal to get it to show the current
progress. (Try something like "pkill -x -USR1 dd")