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Re: dd to clone a drive

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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 
>copy with
>
>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")

Mike Stone

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Thread

dd to clone a drive Jack Dangler <tdldev@gmail.com> - 2017-09-26 16:00 +0200
  Re: dd to clone a drive Roberto C. Sánchez <roberto@debian.org> - 2017-09-26 16:20 +0200
  Re: dd to clone a drive Michael Stone <mstone@debian.org> - 2017-09-26 16:20 +0200
  Re: dd to clone a drive "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-26 16:40 +0200
    Re: dd to clone a drive Michael Stone <mstone@debian.org> - 2017-09-26 17:30 +0200
  Re: dd to clone a drive Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-09-26 16:50 +0200
  Re: dd to clone a drive Gene Heskett <gheskett@shentel.net> - 2017-09-26 17:40 +0200
    Re: dd to clone a drive Jack Dangler <tdldev@gmail.com> - 2017-09-29 13:40 +0200

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