The RC18015xs+ and RXD1215sas are designed to work as a high-availability cluster – requiring two RC18015xs+ and at least one RXD1215sas expansion unit. The units are $3,999.99 and $3,499.99 respectively. With two RC18015xs+ and at least one RXD1215sas expansion unit, the price totals under $12,000. Together, the system delivers state-of-the-art features including: