The Synology RXD1219sas is a high-capacity 12-bay 2U rackmount storage expansion unit designed for seamless scalability with Synology SA3400D high-availability NAS systems. Supporting both 3.5" and 2.5" SAS hard drives and SSDs with hot-swappable drive bays, this expansion unit delivers up to 192TB of total raw capacity for demanding enterprise deployments. Features dual mini-SAS HD input and output ports for high-speed connectivity with minimal data latency, ensuring maximum throughput in mission-critical environments. Built with dual redundant SAS modules and redundant power supplies to maintain continuous uptime during component replacement or maintenance. Plug-and-play design enables quick installation and automatic recognition through Synology DiskStation Manager (DSM) for effortless capacity expansion. Add up to two RXD1219sas units to the SA3400D for a total of 36 drive bays, providing on-demand storage scaling for growing data requirements. Hot-swappable system fans ensure reliable cooling while minimizing service disruptions. Ideal for enterprise data centers, virtualization environments, and high-availability storage clusters requiring flexible, reliable expansion with zero downtime. Backed by Synology's quality engineering and reliability standards for mission-critical business operations.