By Dave Simpson
Start-up Montilio Inc. last month began shipments of a “storage-to-LAN gateway” card that the company claims can boost the performance of single-CPU file servers or NAS appliances and gateways by a factor of 3x to 6x. Priced at $3,899, the RapidFile PCI card is targeted at NFS/CIFS users that want to upgrade or consolidate file servers and/or improve the performance of NAS systems. The standard configuration includes two Gigabit Ethernet ports with TCP/IP offload engines (TOEs) and two 2Gbps Fibre Channel ports (with QLogic chipsets) for connection to a SAN or Fibre Channel disk arrays from any vendor.
The 3x to 6x performance increase depends on the type of I/O. For example, Montilio officials claim that users can realize a 3x improvement with relatively small block sizes and a 6x speedup with large blocks.
According to John Webster, senior analyst and partner at the Data Mobility Group consulting firm, RapidFile’s differentiator is its File Server ReDirector (FSRD) technology, which separates the data and control (metadata) paths. Webster notes that this is analogous to the way in which “intelligent” switches separate the data and control paths, but is unique among accelerator cards. The separation of data and control paths is common in network routers.
How it works
FSRD creates an alternate data path and redirects data between the storage subsystem and the client network (see figure). This approach bypasses the server’s memory and PCI bus, thus boosting performance. Essentially, the technology separates the processing of client requests (e.g., parsing/serving) from the movement of data between storage devices and networked clients. The host processor continues to perform control and maintenance tasks, while RapidFile handles data movement and TCP processing.
A hardware gateway module bridges the host, storage device and network interfaces (see figure on p. 16). The gateway includes a host interface, NFS/CIFS offload engines, DMA, block-level cache, and PCI-X bus-memory switching.
RapidFile software includes Fibre Channel and Gigabit Ethernet drivers and a controller module that runs in the host operating system kernel. Among other functions, the software is responsible for retrieving file-mapping information from the host file system.
The plug-in cards are designed as an alternative to buying more file servers, multi-processor servers, clustered configurations, or proprietary NAS systems and eliminate the need for standard network interface cards (NICs) or Fibre Channel host bus adapters (HBAs). The cards are also positioned as alternatives to RDMA “zero copy” technology and standard TOE accelerator cards.
RapidFile currently works only with Linux (Red Hat and SuSE) platforms. A version for Windows is due in the fourth quarter, with Unix implementations to follow in 2006. Also on the planning board are SCSI and iSCSI implementations.
According to Arun Taneja, consulting analyst and founder of the Taneja Group, Montilio’s RapidFile will compete primarily with established NAS players such as Network Appliance, EMC, and Adaptec/Snap, as well as with “next-generation” NAS servers with global namespace capabilities, such as those from Network Appliance, Isilon, and Panasas (although RapidFile does not include global namespace functionality).