[Linux] USB drive as backup

[Unique Wholesale]

I tried using tar to back my /home directories from a 80 gig drive to the
usb 320gig drive. tar aborted after about 19 gig, giving error that drive
was full. I checked, and only showed a portion occupied. Now, using df on
the harddrive, the /dev/mapping shows full. However, using other checks,
kfilemanager or might be kdiskmanager, the hard drive is on about 40 %
used.
I used tar cvf file.tar /mnt/usbdrive. This does not preserve the
directories under /home. Is there a way to make tar create the
sub-directories?

Also, not sure if related to above, I cannot startx to kde. Last message
on return to prompt is error concernig the usb drive, and trying to fix
something. I removed the usb plug, and commented out the line in the fsta=
b
file, and still get the error. Not at machine now, so cannot furnish exac=
t
error until tonight. I boot up to the login prompt, so still have access
to command line.

What I would like to do at this point is get my /home directory files to
the usb drive and do a new install on the hard drive. If I can still moun=
t
the usb drive, rsync looks like it might work. Again, not sure if it will
preserve directories, but at this point I will take just the files.