How to enable DMA on a SATA drive (was dd backup unbelievably slow on SATA laptop)

Lonni J Friedman netllama at gmail.com
Thu Jan 4 17:11:17 UTC 2007


On 1/4/07, Kevin Kempter <kevin at kevinkempterllc.com> wrote:
> On Thursday 04 January 2007 09:23, Lonni J Friedman wrote:
> > 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.
> All;
>
> How can I enable DMA on a SATA drive in a laptop?

It should be enabled by default.  You could just boot with a Knoppix
CD and then specify the dma parameter at boot time to dd the disk.


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




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