-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Wednesday, 2010-02-03 at 11:52 +0200, Sampsa Riikonen wrote:
Dear List,
A question concerning data backups and transfer speed..
I am trying to do a backup using
dd if=/dev/sda of=/dev/sdb
From my internal hard disk to an external usb hard disk (i.e. I am just dumping the disk image to an empty disk). I am doing this, of course, while the filesystems are unmounted.
I imagine that the bottleneck is the usb (2.0) connection. What I read from wikipedia, the speed of that is..
60 Mbytes (not bits) per second ~ 0.06 Gbytes per second
Yes. That's the maximum, the maintained speed is quite lower.
So this means that a 500 Gbytes hard disk should copy in aprox. 2.3 hours
Yes... :-? I have copied about 50..80 GiB over usb at a time, and it is very slow. I don't remember exactly how slow, though. I should have written it somewhere.
.. but know it seems it takes more than 24 hours!
Could be.
What seems to be the problem? Am I missing something in the math?
Is it a real hard disk, not flash? Something else connected to the usb bus, perhaps?
My external usb hard disk box has also an option to use an esata connector (but then I should buy an adaptor to my laptop), but the speed difference to usb 2.0 is not that big, I imagine..?
It is a "huge" difference, believe me. I have some usb/esata HD boxes, and the speed is so much greater. It goes as fast as an internal HD. There is another advantage: you can run smart tests and learn of the health of the HD. One of my disks was dying, at a young age, and I had no idea. I could have lost the entire backup. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAktpb+kACgkQtTMYHG2NR9VXMACghqqwjwUeN6yMzeZNpO44BIPR DDoAnR+cd5iys7Hpv73hw4N74zMr+kaJ =Cvmt -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org