Questions about the dd command

Marius Gedminas marius at
Fri Feb 29 16:59:49 UTC 2008

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.

> 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
System going down at 5 this afternoon to install scheduler bug.
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