tar(1) File is too long for ustar

[Nuno Morgadinho]

How to use tar(1) to compress ridiculous large files? 

#tar cvfz /dev/rst0 /fitabackup
/fitabackup/server1.tgz
/fitabackup/server3.tgz
* tar: File is too long for ustar /fitabackup/server3.tgz *

server3.tgz has 10.0Gb.