QNAP QXP-820S-B3408. Host interface: PCI Express, Output interface: SAS, Expansion card form factor: Low-profile. Number of fans: 1 fan(s). Data transfer rate (max): 12 Gbit/s. Connectivity technology: Wired, Interface: Fiber

The SAS HBA PCIe Expansion Card is designed for expanding the capacity of a QNAP NAS by connecting it to TL SAS JBOD storage enclosures and REXP expansion units. Multiple expansion units can be daisy-chained via high-speed mini SAS HD cables to expand the total disk capacity up to 4.6PB to meet growing data storage needs. SAS-based storage solutions can assist businesses in creating highly-reliable IT environments for virtualization, surveillance, Big Data, video editing and TV broadcast storage.

Use high-performance and high-availability SAS drives
Compared with SATA, SAS enables low-latency, power-efficient, and IOPS-optimized storage capabilities. Each SAS port combines four 12Gb/s SAS channels, delivering up to 48Gb/s per host connection.

Expand your total disk capacity up to 4.6PB
A NAS with a SAS expansion card can be daisy-chained with up to 16 devices, including TL SAS JBOD storage enclosures and REXP expansion units. This provides to potential to store up to 4.6PB (calculated using 18TB drives in sixteen 16-bay enclosures).

Attain faster backup and uninterrupted services with flexible port configuration
SAS expansion cards can be flexibly configured to fit various usage applications. By managing multipath or link aggregation with NAS to expansion units, data transfer loads are effectively balanced, and you can avoid interrupting system services and prevent backup failures.