>> I don't know.
>> 
>> When using dumping on multiple filesystems it does some kind of
> how to dump simultanously multiple filesystems?
> maybe i don't understand tar.

Sorry, allow me to restate: you can specify multiple files or
directories (not filesystems) to dump.  And as far the multi-process
stuff actually I believe I was speaking from my experience with
SunOS.  It's been a while since I've done this.