We are using zfs filesystem running Solaris on Sparc HW and it's working well, x64 HW is an option for Solaris as well. Go for it.
-- GG >What filesystem and mount options are recommended for a tapetype harddisk? >Details: The amanda-server is a Debian 5 (lenny) host. >The tape size is 40 gigs. The filesystems are about 540, 990, and 950 gigs.