. SYSTEM ARCHITECTURE The BlueDBM architecture is a homogeneous cluster of host servers coupled with a BlueDBM storage device (see Figure 2(a)). Each BlueDBM storage device is plugged into the host server via a PCIe link, and it consists of flash storage, an in-store processingengine,multiplehigh-speednetworkinterfaces,andon-boardDRAM.Thehost servers are networked together using Ethernet or other general-purpose networking fabric. The host server can access the BlueDBM storage device via a host interface implemented over PCIe. It can directly communicate either with the flash interface, to treat is as a raw storage device, or with the in-store processor, to perform computation on the data. When the host wants to access remote storage, instead of requesting data fromaremotehost,itcandirectlyrequestdatafromtheremotestoragedeviceoverthe integrated storage network. This removes multiple passes of the network and storage software stacks, improving performance greatly. The in-store processing engine has access to four major services: the flash interface, network interface, host interface, and on-storage DRAM buffer. Figures 2(a) and 2(b) show the four services available to the in-store processor. In the following sections, we