Sonnet engineering has fixed this issue with some Fusion storage systems. This issue was addressed and fixed as follows:
APRIL, 2008: in Fusion D400Q and Fusion D500P systems with serial numbers beginning with J.
MAY 20, 2008: In Fusion D800RAID with serial numbers beginning with G.
All versions of Fusion R400Q and R800RAID are compatible with Seagate ES.2 Drives.
Note: Seagate ES.2 drives have lower performance than Sonnet recommended drives.
You are using a SATA port that is not port-multiplier aware. For example, the internal SATA ports in a Mac Pro that may be brought to the PCIe rear panel via an eSATA extender cable are not port-multiplier aware. All of Sonnet's Tempo SATA cards with external ports are port-multiplier aware.