Changes

The EHL consists of a dual-thermal-zone (cold/hot) rackmount cabinet with power conditioning and backup, power distribution, thermal monitoring, and 1- and 10-gigabit network services. This cabinet supports a large number of hyperscale and SOC-based ARM computersfor various applied research projects. == Equipment Detail ==

For details === Cabinet === The EHL cabinet is a [http://www.silentium.com/?page_id=33 Silentium Accoustirack Active], a full-height acoustically-insulated rackmount cabinet with two fan units. The lower fan unit takes air from outside the cabinet and blows it up the front of the rackmount equipment area (cold zone). Air passes through the individual devices and is vented out the back of each units into the hot zone. A second fan unit exhausts air from the hot zone out the top of the cabinet. Each of the fan units includes active noise cancellation so that the loaded rack can be operated in a software development lab context. After the fan units are installed, there are [http://en.wikipedia.org/wiki/Rack_unit 33u] available for other devices. === Power === Power is provided by two 115 volt, 15 amp, 60 cycle circuits that power to independent APC 1.5 kW rackmount power supplies. Each of the power supplies has a network interface for remote monitoring and control. The UPSes feed two Raritan Dominion power distribution units (PDUs), mounted vertically up the sides of the cabinet at the back. The PDUs act like long power bars, but have control and monitoring systems so that the current consumption can be measured for each outlet and remotely monitored over the network, using snmp or http protocols. Each outlet can also be switched on or off under network control. Where possible, devices have been configured with dual power supplies. This means that many of the devices in the equipment EHL are plugged into both PDUs and can continue to operate when power is cut to one of the two supplies. This permits the EHL to be rewired without any downtime; it also guards against downtime due to PDU, UPS, or PSU failure. Devices which are not configured with dual PSUs are connected to just one of the PDUs. === Environmental Monitoring === One of the PDUs is equipped with a string of three environmental sensors. These are laid out diagnonally across the EHL, so that the air intake temperature, mid-cabinet hot zone temperature, and air exit temperatures are monitored, as well as the humidity. === Networking === One Cisco 24-port gigabit switch and one Netgear 24-port 10-gigabit switch are installed in the back of the EHL. The 10g switch provides both 10GBASE-T and SFP+ connections. Where possible, SFP+/DA (Direct Attach) copper cables are used because they are simpler and less expensive than fibre optic cables, see and yet offer much lower latency than 10GBASE-T connections (2 nS vs 2 mS - one million times less latency). Devices which do not support SFP+ are connected with 10GBASE-T. Connections between the LAN in the EHL and the outside world are provided by a [http://www.compulab.co.il/utilite-computer/web/utilite-overview Utilite], a small ARM computer. This computer acts as a [http:Category//www.diablotin.com/librairie/networking/firewall/ch04_02.htm dual-homed host] that provides firewall, NAT, forwarding, DNS, and VPN endpoint services. === Storage === Storage is provided by a Synology Diskstation rackmount device, which provides both storage area network (SAN, raw block devices over protocols such as iSCSI) and network-attached storage (NAS, filesystem-level shared block devices over protocols such as NFS and SMB). It is populated with twelve 1 TB SSDs and equipped with dual power supplies and dual 10-gigabit ethernet. === Terminal Server === Many of the computers installed in the EHL do not have video output (because they're not intended for desktop applications). Most of these have a serial port; in many cases, the serial port can be accessed using the ICMP SOL (Serial-over-LAN) protocol on the network. Since this is not a TCP/IP protocol, the client must run somewhere on the LAN. For systems that do not have a woring ICMP engine, the EHL is equipped with a [[Cyclades Terminal Server]] for remote access. === Display === The EHL is equipped with a 15" 4:Enterprise Hyperscale Lab|Enterprise Hyperscale Lab category page3 LCD monitor, bolted to a 4u blanking panel. This display is driven by a Raspberry Pi, and can be used to show educational information about the rack, current system status information, or diagnostic data. === Calxeda Energy Core 1000 System === 32-bit ARM compute is provided by a Calxeda Energy Core ECX-1000 system provided by Boston Limited. There are four installed "Energy Cards", each with 4 ECX-1000 nodes, which have a quad-core ARM Cortex-A9 processor and a small ARM management processor. This system runs the [[Pidora]]build system (except for the Koji hub and web nodes). === 64-Bit ARM Compute === The EHL also has over 100 cores of ARM64 compute, provided by a number of systems from multiple vendors. These systems provide a build system and testing platforms for software optimization, used for applied research on ARM64 systems.