Just for curiosity.
I’m doing a full backup of my laptop, using a dd image of all the partitions, plus an rsync backup
of the home and root partitions. The destination hard disk is connected via usb, so there is a speed
limit of about 30 MB/s
The system is doing nothing except this, as I’m running the xfce rescue image from a usb stick.
Home takes 146 minutes to dd, and over 202 minutes to rsync. And for rsync I skip the leafnode nntp
database, a directory holding over 82000 small files; it would take way longer if I had not skipped
(The entire 500 GB HD took 4.4897 hours to dd - over usb)
So, there is a large speed advantage to using dd
In theory, there is a speed advantage using rsync if it is a second attempt, because many files are
the same and thus not copied again. But, as I’m using “–checksum”, that advantage is lost. It is
the first backup copy, anyway, so the checksum calculation is not done now.
(I do a second run of the rsync to make sure the copy is entirely correct, via that checksum).
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Elessar))