Topics. CIT 470: Advanced Network and System Administration. Google DC in The Dalles. Google DC in The Dalles. Data Centers

Transcription

1 CIT 470: Advanced Network and System Administration Data Centers Topics Data Center: A facility for housing a large amount of computer or communications equipment. 1. Racks 2. Power 3. PUE 4. Cooling 5. Containers 6. Economics CIT 470: Advanced Network and System Administration Slide #1 Google DC in The Dalles Google DC in The Dalles Located near 3.1GW hydroelectric power station on Columbia River Inside a Data Center Inside a Container Data Center 1

2 Data Center is composed of: Data Center Components A physically safe and secure space Racks that hold computer, network, and storage devices Electric power sufficient to operate the installed devices Cooling to keep the devices within their operating temperature ranges Network connectivity throughout the data center and to places beyond Data Center Tiers See for more details about tiers. Racks: The Skeleton of the DC 19 rack standard EIA-310D Other standard numbers. NEBS 21 racks Telecom equipment. 2-post or 4-post Air circulation (fans) Cable management Doors or open Rack Units Rack Sizes 2

3 Rack Purposes Organize equipment Increase density with vertical stacking. Cooling Internal airflow in rack cools servers. Data center airflow determined by arrangement of racks. Wiring Organization Cable guides keep cables within racks. Rack Power Infrastructure Different power sockets can be on different circuits. Individual outlet control (power cycle.) Current monitoring and alarms. Network managed (web or SNMP.) Rack-Mount Servers Blade Servers 1U 4U Buying a Rack Buy the right size Space for servers. power, patch panels, etc. Be sure it fits your servers. Appropriate mounting rails. Shelves for non-rack servers. Environment options Locking front and back doors Sufficient power and cooling. Power/environment monitors. Console if needed. Space Aisles Wide enough to move equipment. Separate hot and cold aisles. Hot spots Result from poor air flow. Servers can overheat when average room temperature is too low. Work space A place for SAs to work on servers. Desk space, tools, etc. Capacity Room to grow. 3

4 Data Center Power Distribution UPS (Uninterruptible Power Supply) Provides emergency power when utility fails Most use batteries to store power Conditions power, removing voltage spikes Standby UPS Power will be briefly interrupted during switch Computers may lockup/reboot during interruption No power conditioning Short battery life Very inexpensive Online UPS AC -> DC -> AC conversion design True uninterrupted power without switching Extremely good power conditioning Longer battery life Higher price Power Distribution Unit (PDU) Estimating Per-Rack Power Takes high voltage feed and divides into many 110/120 V circuits that feed servers. Similar to breaker panel in a house. 4

5 The Power Problem 4-year power cost = server purchase price. Upgrades may have to wait for electricity. Power is a major data center cost $5.8 billion for server power in $3.5 billion for server cooling in $20.5 billion for purchasing hardware in Measuring Power Efficiency PUE is ratio of total building power to IT power; efficiency of datacenter building infrastructure SPUE is ratio of total server input to its useful power, where useful power is power consumed by CPU, DRAM, disk, motherboard, etc. Excludes losses due to power supplies, fans, etc. Computation efficiency depends on software and workload and measures useful work done per watt Power Usage Effectiveness (PUE) Data Center Energy Usage PUE = Data center power / Computer power PUE=2 indicates that for each watt of power used to power IT equipment, one watt used for HVAC, power distribution, etc. Decreases towards 1 as DC is more efficient. PUE variation Industry average > 2 Microsoft = 1.22 Google = 1.19 Sources of Efficiency Losses UPS 88-94% efficiency Less if lightly loaded PDU voltage transformation.5% or less Cables from PDU to racks 1-3% depending on distance and cable type Computer Room Air Conditioning (CRAC) Delivery of cool air over long distances uses fan power and increases air temperature Cooling a Data Center Keep temperatures within C Cooling equipment rated in BTUs 1 Watt = 3412 BTUH BTUH = British Thermal Unit / Hour Keep humidity between 30-55% High = condensation Low = static shock Avoid hot/cold spots Can produce condensation 5

6 Computer Room Air Conditioning Waterworks for Data Center Large scale, highly reliable air conditioning units from companies like Liebert. Cooling capacity measured in tons. Estimating Heat Load Hot-Cold Aisle Architecture Server air intake from cold aisles Server air exhaust into hot aisles Improve efficiency by reducing mixture of hot/cold Free Cooling Cooling towers dissipate heat by evaporating water, reducing or eliminating need to run chillers Google Belgium DC uses 100% free cooling Improving Cooling Efficiency Air flow handling: Hot air exhausted by servers does not mix with cold air, and path to cooling coil is very short so little energy spent moving Elevated cold aisle temperatures: Cold aisle of containers kept at 27 C rather than C. Use of free cooling: In moderate climates, cooling towers can eliminate majority of chiller runtime. 6

7 Latency Server PUE (SPUE) Primary sources of inefficiency Power Supply Unit (PSU) (70-75% efficiency) Voltage Regulator Modules (VRMs) Can lose more than 30% power in conversion losses Cooling fans Software can reduce fan RPM when not needed SPUE ratios of are common today Power Supply Unit Efficiency 80 PLUS initiative to promote PSU efficiency 80+% efficiency at 20%, 50%, 100% of rated load Can be less than 80% efficient at idle power load First 80 PLUS PSU shipped in 2005 Server Useful Power Consumption Server Utilization ~10-50% Device Power Usage Intel Xeon W GHz Quad Core 130 W Intel Xeon E GHz Quad Core 80W Intel Xeon E GHz Dual Core 80W 7200RPM Hard Drive 7W 10,000RPM Hard Drive 14W 15,000RPM Hard Drive 20W DDR2 DIMM 1.65W Video Card W The Case for Energy-Proportional Computing, Luiz André Barroso, Urs Hölzle, IEEE Computer, December 2007 It is surprisingly hard to achieve high levels of utilization of typical servers (and your home PC is even worse) The best method to determine power usage is to measure it Figure 1. Average CPU utilization of more than 5,000 servers during a six-month period. Servers are rarely completely idle and seldom operate near their maximum utilization, instead operating most of the time at between 10 and 50 percent of their maximum Server Power Usage Range: % The Case for Energy-Proportional Computing, Luiz André Barroso, Urs Hölzle, IEEE Computer, December 2007 Energy efficiency = Utilization/Power Server Utilization vs. Latency Figure 2. Server power usage and energy efficiency at varying utilization levels, from idle to peak performance. Even an energy-efficient server still consumes about half its full power when doing virtually no work. Utilization 100% 7

8 Improving Power Efficiency Improving Power Efficiency Application consolidation Reduce the number of applications by eliminating old applications in favor of new ones that can server the purpose of multiple old ones. Allows elimination of old app servers. Server consolidation Use single DB for multiple applications. Move light services like NTP onto shared boxes. Use SAN storage Local disks typically highly underused Use SAN so servers share single storage pool Improving Power Efficiency Virtualization Host services on VMs instead of on physical servers Host multiple virtual servers on single physical svr Only-as-needed Servers Power down servers when not in use Works best with cloud computing Granular capacity planning Measure computing needs carefully Buy minimal CPU, RAM, disk configuration based on your capacity measurements and forecasts Data Center in a shipping container. 4-10X normal data center density. 1000s of servers. 100s of kw of power. Advantages Efficient cooling High server density Rapid deployment Scalability Containers Vendor offerings: Microsoft Chicago Data Center Google Container Patents Containers docked at central power spline Vertical stack of containers Container air flow diagram, with a center cold aisle and hot air return behind servers 8

9 Data Center Failure Events Key Points Data center components Physically secure space Racks, the DC skeleton Power, including UPS and PDU Cooling Networking Power efficiency (server cost = 4 years power on avg) PUE = Data center power / IT equipment power Most power in traditional DC goes to cooling, UPS SPUE = Server PUE; inefficiencies from PSU, VRM, fans Cooling Heat load estimation Air flow control (hot/cold aisle architecture or containers) Higher cold air temperatures (27C vs. 20C) Free cooling (cooling towers) TCO = DC depr + DC opex + Svr depr + Svr opex References 1. Luiz Andre Barroso and Urs Holzle, The Case for Energy- Proportional Computing, IEEE Computer, Vol 40, Issue 12, December Luiz Andre Barroso and Urs Holzle, The Datacenter as a Computer: An Introduction to the Design of Warehouse-Scale Machines, 1st edition, Morgan and Claypool Publishers 3. Xiaobo Fan, Wolf-Dietrich Weber, Luiz Andre Barroso, Power provisioning for a warehouse-sized computer, ISCA '07: Proceedings of the 34th annual international symposium on Computer architecture 4. Thomas A. Limoncelli, Christina J. Hogan, and Strata R. Chalup, The Practice of System and Network Administration, Second Edition, Addison-Wesley Professional, Evi Nemeth, Garth Snyder, Trent R. Hein, Ben Whaley, UNIX and Linux System Administration Handbook, 4 th edition, Prentice Hall,