I finally found some time to do a crude performance analysis of my home-grown D2D backup configuration. I started off attaching the two USB disk to a Sun Blade 150. As per a previous comment, with the Sun Blade only support USB1.1 transfer rates, the performance was pretty bad. It took in the order of 15 minutes to backup 1GB of data. With approximately 4Gb worth of pictures and video files to backup, I gave up on this setup.
I attached the two drives to another server, that supports USB2.0. Again, running OpenSolaris, and again the same ZFS configuration as mentioned in my previous blog entry.
To get a feel for the performance, I created a 1Gb file called "bigfile" on another Solaris box on my network. Then I copy it over to my backup server with as follows :
$ time scp bigfile georg:/backup/ge29057 real 3m9.760s user 2m0.063s sys 1m3.858s
So, 3 minutes to backup 1Gb of data. That's approx 12 minutes for a complete backup of all my pictures and video files. That's good enough for me.