I've published two papers to BigAdmin on how to use the Sun Fire X4500 as a large disk cache for disk-based backups with Symantec Netbackup and Sun's own Sun StorageTek Enterprise Backup Software. Sun Fire X4500 Server as Storage Node for Sun StorageTek Enterprise Backup Softwware 7.4 Sun Fire X4500 as a Media Server for Symantec Veritas Netbackup 6.5 Both papers discuss using the X4500 running Solaris10 and the ZFS Filesystem to present a large (10-15TB) amount of disk-cache for fast backups and restores. Check them out. Your feedback is welcome on the BigAdmin Wiki discussion pages.