DD not working--SUCCESS!
Ian Malone
ibmalone at gmail.com
Fri Aug 31 16:36:04 UTC 2007
Robert P. J. Day wrote:
> On Fri, 31 Aug 2007, Ian Malone wrote:
>
>> Karl Larsen wrote:
>>> Jacques B. wrote:
>>>> Because the clone would be of a
>>>> running system. So booting from it would be comparable to booting
>>>> from a system that crashed (I'm making an educated guess at that one).
>>>>
>>> Not a good guess. To use DD you need a computer with dd and a fast cpu. I
>>> did top while dd was working and it was taking 70% of the cpu's time :-P
>>>
>> It's one of the oldest Unix programs: it will copy as fast as your
>> system can go. Yes, a fast system will copy faster.
>
> i'm guessing he failed to provide a decent blocksize so dd was using
> the default blocksize of 512 bytes. that will slow things down in a
> hurry.
>
How would you go about estimating a decent blocksize (other than by
testing)? My first instinct would be to go for some percentage of
the drive's cache. (And it had better be a factor of the amount you
want to copy I suppose.)
--
imalone
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