Questions about the dd command

Heinrich Rebehn rebehn at
Fri Feb 29 17:53:15 UTC 2008

Marius Gedminas wrote:
> On Fri, Feb 29, 2008 at 05:40:27PM +0100, Heinrich Rebehn wrote:
>> 1. You should not use dd to copy a filesystem that is currently mounted, 
>> because parts of it may be cached in RAM. The copy would be 
>> inconsistent. So you better boot from a ubuntu CD.
>> 2. Standard dd does not have a "progress bar" option. However, it will 
>> report its progress when sent a SIGHUP.
> The manual says SIGUSR1, not SIGHUP.

Sorry! :-(

>> 3. I don't know, make measurements yourself. 1440 is a somewhat strange 
>> value, use a multiple of 512 (The standard blocksize)
> I usually stick with bs=1K.
> Marius Gedminas


More information about the ubuntu-users mailing list