dd backup unbelievably slow on SATA laptop

Lonni J Friedman netllama at gmail.com
Thu Jan 4 16:23:37 UTC 2007


On 1/4/07, Kevin Kempter <kevin at kevinkempterllc.com> wrote:
> Hi List;
>
> I have FC5 on an IBM Thinkpad Z60m with 2G of RAM and a 100G SATA HD.  I also
> have a removeable CD/DVD drive and I can insert a HD adapter into
> the "ultrabay" which adds a second HD attached to the main bus (as the CD/DVD
> would be).
>
> I inserted the second 100G ATA HD into the ultrabay and booted into single
> user mode. The second HD shows up as /dev/hdc my main HD shows up
> as /dev/sda.  (Note if I boot with hdc=noprobe into single user mode then the
> system is not aware of the root user)
>
> I run this:
> dd if=/dev/sda of=/dev/hdc bs=64K &
> pid=$!
>
> Note: I've tried the same with bs=128K, bs=1M, bs=256K and with no bs tag at
> all with the same results
>
> Then I check the progress from time to time with this:
> kill -USR1 $pid
>
> I find that my avg speed in 1.7m/sec which leads to a full backup time of
> around 16-17 hours.
>
> Before the deal with M$ I used to run SuSE 10 and was able to do a dd on the
> same laptop inside of 4 hours.
>

It sounds like DMA is disabled.


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L. Friedman                                    netllama at gmail.com
LlamaLand                       http://netllama.linux-sxs.org




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