[plug] dd speed estimates and /dev/hdx grepping

[James Devenish]

In message <001b01c3988c$17a02340$3f00020a at itdeskxp>
on Wed, Oct 22, 2003 at 07:03:07PM +0800, Ryan wrote:
> Does anyone have *any* idea how long a dd might take in the following
> situation assuming everything is hunky-dory?
> 
> Celeron 300 - 128MB RAM, two identical 40GB 7200RPM drives, booted with
> Debian 3.0 CD, dropped to console and:
> 
> dd if=/dev/hdd of=/dev/hda 

1/ bus architectures?
2/ bus speeds?
3/ bus configurations?

> It has been going for 5 hours so far with no errors - when I switch back to
> the install console the screen redraw is VERY slow - indicating the machine
> is doing some thinking.

Something like iostat or hdparm could give you an indication of the
current throughput, from which you could calculate the times.

> On the another note, if one wanted to grep a filesystem image for stuff, can
> one do that directly on a device or would it need to be dd'd into one or
> many standard files first?  'grep -b blah /dev/hda' or similar is not
> doable, is there a way to do such a thing on an in-tact hard drive without
> imaging it to file(s)?

Not doable? Are you sure?



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