Jeremy Chadwick schrieb:
On Fri, Oct 31, 2008 at 03:36:02PM +0100, Christoph Kukulies wrote:
Ivan Voras schrieb:
Jeremy Chadwick wrote:
On Fri, Oct 31, 2008 at 09:48:16AM +0100, Christoph Kukulies wrote:
What would be the fastest way to do that sector by sector copy? I'm
using dd right now,
dd if=/dev/ad0 of=/dev/da0 bs=10000000
On the flip side, your blocksize (bs) there is quite high for no good
reason. I'd pick something more like bs=64k or bs=128k. The default
(512) is too small for what you want, but 10MBytes is silly.
Not only that, but "10000000" isn't even correct - it needs to be a
multiple of sector size. Generally, using suffixes will do the right thing:
dd if=/dev/ad0 of=/dev/da0 bs=1m
OK, I understand that 10000000 isn't good, I just thought it wouldn't
harm. But if it is a transfer rate killer then I'd better think of
typing ^C now. The command is running for 6 hours now.
Six hours? Hmm... That seems too long, but of course the FreeBSD USB
stack is involved, and a USB device in general. I would have assumed
that copy should have finished after 2-3 hours tops.
An idea how I can check the current amount of transfered byed alongside
the running dd command? Or watch the current i/o rate?
iostat or gstat (I'm willing to bet you prefer the latter) will get you
what you want, more or less.
The job just finished and I have a figure of the Ubuntu performance,
with the unfortunate blocksize parameter though, so I think it isn't
much worth. Anyway here is the figure of the
above dd command copying 500GB to a WDC disk in an Icy box.
50010+1 Datensätze ein
50010+1 Datensätze aus
500107862016 Bytes (500GB) kopiert, 25787,9 s, 19,4 MB/s
Will do that using FreeBSD next time.
Thanks a lot so far.
--
Christoph
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