> 
> specify a (conservatively estimated) value of tape capacity in kilobytes
> with -B.
> And no, I don't think it's a good idea using the drive's compression
> mechanism for _backups_...

why?!
 
> 2) how to dump all filesystems mentioned in fstab with nonzero dump flag?
> 
> well, basically you dump one after the other :)
> use /dev/nrst0 (the non-rewind-on-close device) if you want to keep
> more than one dump per tape, and use mt for positioning.
i've done that..