View the refurbished HP Smart Array P841/4GB FBWC 12Gb 4-ports Ext SAS Controller 726903-B21 750051-001 Quickspecs here
The HP Smart Array P841 Controller is a full height, PCIe3 x8, 12Gb/s Serial Attached SCSI (SAS) RAID controller that provides enterprise-class storage performance, increased external scalability, and data protection for select HP ProLiant Gen9 rack and tower servers. It features sixteen external physical links and delivers increased server uptime by providing advanced storage functionality, including online RAID level migration (between any RAID levels) with 4GB flash back write cache (FBWC), global online spare, and pre-failure warning. This controller includes transportable FBWC allowing the data in the cache to be migrated to a new controller.
The Gen9 family of controllers supports the HP Smart Storage Battery. With HP Smart Storage Battery, multiple Smart Array controllers are supported without needing additional backup power sources for each controller, resulting in simple upgrade process