HP ProLiant power supply technology

HP ProLiant power supply technology technology brief Abstract... 2 Introduction... 2 HP common-slot power supplies... 3 Capacities and efficiencies of common-slot power supplies... 4 Load-Balanced and High Efficiency Modes... 6 Right-sizing the supply to the server... 8 Reducing hardware cost... 8 Avoiding trapped power capacity... 8 HP Power Advisor... 8 Installation considerations with common-slot power supplies... 10 Conclusion... 11 For more information... 11 Call to action... 11

Abstract The cost of energy needed to run an enterprise data center can account for the majority of a data center s total operating costs. These days it is the power budget, not floor or rack space, which constrains a data center s computing capacity. This technology brief describes how common-slot power supplies boost energy efficiency and reduce operating costs. Introduction The demand for computing, storage, and networking capacity continuously increases. Moreover, the cost of powering that capacity is growing. Gartner Research predicts that power costs will be nearly 50 percent of the overall IT budget by the end of 2009. Finding ways to use power more wisely will make it possible to increase data center computing capacity without exceeding the power budget. Power (watts) can be saved at several levels within the facility: IT processing equipment, cooling equipment, and power distribution infrastructure. However, power saved at the IT processing level (server, storage, and networking components) will result in the greatest return on savings. For the latest generation of server products, HP has implemented Thermal Logic technology, which includes innovations aimed at reducing energy consumption and extending the life of the data center. Thermal Logic technology includes several elements working together to reverse the generational trend of rising power consumption in servers (Figure 1). Figure 1. Reversing a trend: power consumption history of ProLiant servers 800 700 Year 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Power (watts) 600 500 400 300 200 100 ProLiant generation G1 G2 G3 G4 idle/max G5 idle/max G6 idle/max A key element of Thermal Logic technology is the HP common-slot power supply. 2

HP common-slot power supplies HP common-slot power supplies share a common electrical and physical design that allows installation in server platforms with a common-slot power supply bay (Figure 2). HP common-slot power supplies are compatible with over 90% of HP ProLiant G6 servers. Figure 2. ProLiant server platforms that support HP common-slot power supplies ProLiant DL300 G6 series (DL385, DL380, DL370, DL360, DL320) ProLiant DL580 G5 ProLiant DL100 G6 series (DL180, some DL160 models) ProLiant DL785 G5/G6 ProLiant ML300/100 G6 series (ML370, ML350, ML330, ML150) HP common-slot power supply ProLiant DL1000 series ProLiant c3000 enclosure ProLiant SL6000 series Use of common-slot power supplies across platforms simplifies maintenance for an IT department. Data centers based on platforms using a common power supply require fewer maintenance spares, which saves on the cost of inventory and facility space. NOTE Common-slot power supplies are qualified with specific ProLiant servers according to power supply capacity. These qualifications are defined in the section Installation considerations with commonslot power supplies. 3

Capacities and efficiencies of common-slot power supplies HP common-slot power supplies are available in four types (Figure 3). The 460-W and 750-W supplies operate at 92% efficiency (on average) and have achieved an 80 PLUS Gold rating. The 1200-W AC supply can operate at 90% efficiency (on average), earning an 80 Plus Silver rating. The 1200-watt -48 VDC supply is designed for installations that use a power infrastructure based on the telecommunications standard of -48 Volts DC for distributing power to IT equipment. This range of available capacities allows system administrators to maintain high operating efficiency during server re-configurations for both up-grading and down-grading. The 80 PLUS certification is an incentive program funded by electric utilities to encourage manufacturer development and customer application of more energy-efficient power supplies. To earn 80 PLUS certification, a power supply (PS) must be proven through independent testing to be 80% (or greater) energy efficient when delivering 20, 50, and 100% of the rated load capacity with a true power factor of 0.9 or greater. Power supply qualifications include 80 PLUS, 80 PLUS Bronze, 80 PLUS Silver, or 80 PLUS Gold certification. For more information on the 80 PLUS program, visit the following website: http://www.80plus.org Figure 3. HP common-slot power supply models 460-watt supply (100-240 VAC) 750-watt supply (100-240 VAC) 1200-watt supply (100-240 VAC ) 1200-watt supply (-48 VDC ) Table 1 includes efficiency data collected by the Electric Power Research Institute (EPRI) during 80 PLUS measurement tests for HP common-slot power supplies operating from 230 VAC. Table 1. Operating efficiencies of HP common-slot power supplies Percent of efficiency Power supply type @ 20% load @ 50% load @ 100% load 80 PLUS Certification 460-watt 90.70% 93.20% 92.81% Gold 750-watt 91.33% 94.58% 92.57% Gold 1200-watt (AC) 86.84% 91.75% 91.19% Silver NOTES: Most common load point 4

Figure 4 shows an efficiency comparison of 460-W and 750-W HP common-slot power supplies for ProLiant G6 servers and the power supply of the earlier generation DL380 G5 server. Throughout most of the operating range of the power supplies, the G6 supplies offer a significant improvement in efficiency over the G5 supply. For instance, at an output load of 300 watts or less (often the case for redundant, load-sharing supplies), the 460-W and 750-W G6 supplies offer a 7% to 15% improvement over the G5 supply. NOTE HP common-slot power supplies designed for AC input voltage are auto-ranging from 100 to 240 VAC. For maximum efficiency, HP recommends operating these supplies at high-line voltages (200 240 VAC). Figure 4. Efficiency comparison of HP common-slot power supplies (G6) to the HP ProLiant G5 power supply 94% 92% 90% 88% Efficiency 86% 84% 82% 80% 70% 0 100 200 460-W G6 power supply 300 400 500 Power (watts) 600 700 800 750-W G6 power supply DL380 G5 power supply As shown in Figure 5, the common-slot power supplies achieve maximum efficiency when operating in the mid to upper range of their rated capacity. 5

Figure 5. Peak efficiency ranges for 460-watt, 750-watt, and 1200-watt AC-input common-slot power supplies Peak efficiency range for 460-W supply Peak efficiency range for 750-W supply Peak efficiency range for 1200-W (AC) supply Efficiency Power (watts) 750W, 92% 460W, 92% 1200W (AC input), 90% To achieve the highest efficiency, the customer needs to match the power loads to the power supply and decide if redundant power supplies are going to be operating in Load-Balanced or High Efficiency mode. Load-Balanced and High Efficiency Modes An HP ProLiant server configured with the 460-watt or 750-watt common-slot power supply supports three operating scenarios: A: Operating with a single supply B: Operating with redundant supplies in Load Balanced Mode C: Operating with redundant supplies in High Efficiency Mode As shown in Figure 6A, a single 750-watt power supply supporting the entire load of the server can achieve high efficiency when operating in the mid to upper range of its capacity. In this scenario, redundancy is not provided. Figure 6B shows the efficiency curve for redundant 750-watt supplies operating in Load-Balanced Mode, which is enabled by default in redundant configurations. In Load-Balanced Mode, the load is shared equally between the two supplies. Over much of the server s operating range, Load-Balanced Mode results in a significant efficiency penalty compared to a single power supply supporting the entire load. When High Efficiency Mode is enabled, each power supply in the server is designated as either a primary or secondary supply and the entire server load is shifted to the primary power supplies. This allows the primary power supplies to operate at higher efficiency points on the load curve while the secondary power supplies operate in idle mode, providing no output power and consuming very little power (typically two to four watts per supply). The result, as shown in Figure 6C, is that High Efficiency Mode achieves efficiency levels that come close to those of a single supply system. 6

As indicated in Figure 6C, High Efficiency Mode with 750-watt supplies is beneficial for loads up to approximately 525 watts. For loads requiring more than 70% of the primary power supply capacity, Load-Balanced Mode offers better efficiency. Figure 6. Comparison of efficiencies between single and redundant 750-W power supplies 93% A: Single 750-watt supply Efficiency 91% 89% 87% 85% 0 100 200 300 400 500 600 700 Output load (watts) 93% B: Redundant 750-watt supplies in Load-Balanced Mode Efficiency 91% 89% 87% 85% 0 100 200 300 400 500 600 700 Output load (watts) 93% C: Redundant 750-watt supplies in High Efficiency Mode Efficiency 91% 89% 87% Efficiency penalty compared to single supply operation 85% 0 100 200 300 400 500 600 700 Output load (watts) NOTE High Efficiency Mode also reduces energy consumption when the server is off. During this time, all secondary supplies consume less than one watt. High Efficiency Mode is enabled through the server s ROM-Based Setup Utility (RBSU) under System options Redundancy options. When enabling High Efficiency Mode, the user can specify that the odd or even power supplies will be designated manually or automatically as secondary supplies. This flexibility allows users to balance the load across a rack manually or automatically. 7

Right-sizing the supply to the server The availability of common-slot power supplies in multiple capacities allows IT technicians to match the power supply capacity to the actual load of a server configuration; that is, to select the right-size supply. In addition to increased efficiency, right-sizing the power supply also offers two immediate benefits: reducing hardware cost and avoiding trapped power capacity. Reducing hardware cost Smaller capacity supplies cost less to purchase than larger capacity supplies. Nevertheless, IT infrastructure designers often configure servers with larger-than-necessary supplies to allow for future expansion or upgrades. For the purchase of hundreds or more servers, the savings from ordering only the capacities actually needed can be significant. Avoiding trapped power capacity Depending on location, large data centers may be required by law to size their power circuit (that is, their availability of power to the facility) based on the servers maximum power supply output rating or faceplate rating. This method of provisioning can quickly use up the data center power budget. Most servers, even fully configured servers operating at 100% utilization, will typically require only 70% of the power supply capacity. If only 70% of power (at the most) will ever be used, the data center will not be able to expand because of the circuit power is trapped based on the required method of provisioning. If power supplies that more closely match the required power are used, the trapped capacity can be reclaimed to power more equipment while staying in the same power budget. HP Power Advisor The HP Power Advisor utility removes much of the guesswork from estimating the power requirements of a particular HP ProLiant server configuration. Developed from actual measurement data collected from ProLiant servers running under heavy load, the Power Advisor allows the IT/facilities technician to build a virtual server system and accurately pre-calculate the power needs of the server configuration without having to assemble and run the hardware. Figure 7 shows a typical screen from a Power Advisor calculation for a ProLiant DL180 G6 server. The Power Advisor allows the user to select precise configuration parameters such as processor type, memory size, and drives. As the configuration is being made, the Power Advisor continuously calculates the Current Configuration Wattage Estimate. A Utilization slider control allows the user to set the projected degree of server utilization. 8

As shown in Figure 7, if the server configuration or utilization exceeds the limits of the default 460-W unit, the Power Advisor generates an error message suggesting a power supply upgrade. It also allows the user to add a redundant supply if applicable. Figure 7. Calculating power needs of an HP DL180 G6 server configuration: Once a server configuration is complete, the user can build a complete rack of servers with the same configuration or with unique configurations. Complete rows of server racks can be assembled virtually so that an accurate pre-estimate of power requirements can be determined for a data facility. NOTE The Power Advisor allows users to avoid initial configuration mistakes such as using an under-rated power supply. The Power Advisor should also be consulted before reconfiguring a server. The HP Power Advisor can be downloaded from the following URL: http://www.hp.com/go/hppoweradvisor. The HP Power Advisor allows IT architects to choose the right size power supply for a given server configuration. This saves money in the initial acquisition by allowing the purchase of less expensive, smaller-capacity supplies and results in more efficient operation for energy savings. 9

Installation considerations with common-slot power supplies Although the common-slot power supply design allows cross-platform installation, HP has qualified only the specific ProLiant server and partner products listed in Table 2 for use with the indicated power supply types. Table 2. Products for which common-slot power supplies have been qualified Common-slot power supply type Qualified products 460-W 100-240 VAC ProLiant ML350 G6, DL160G6, DL180 G6, DL320 G6, DL360 G6, DL380 G6, DL385 G6, DL1000 G6, and SL6000 G6 servers, D2000 Disk Enclosure 750-W 100-240 VAC ML150 G6, ML330 G6, ML350 G6, ML370 G6, DL160 G6, DL180 G6, DL360 G6, DL370 G6, DL380 G6, DL385G5p, DL385G6, DL1000 G6 and SL6000 G6 1200-W 100-240 VAC ProLiant DL360 G6, DL370 G6, DL380 G6, DL385 G5p, DL385G6, DL785 G5, DL785 G6, DL1000 G6 and SL6000 G6 servers, ProCurve 6600 switches, AdvanceStack Dial-A-LAN 2A and 4A modules, Wired Advance Accessories 1200-W -48 VDC DL380 G6, DL385 G6, DL580 G5, and c3000 HP ProLiant servers that support redundant power supplies only allow installation of same-type supplies. A power supply mismatch or an unsupported power supply will result in an error indication as described in Table 3. Table 3. Common-slot power supply error conditions Condition Power supply mismatch detected during boot Power supply mismatch detected during runtime Unsupported power supply detected during boot System Insight Display Indication Power supply LED (all supplies) blinking amber Power supply LED (added supply only) blinking amber Power supply LED (added supply only) blinking amber Description BIOS ROM will power up power supply #1 and then halt. ilo will detect the mismatch and not allow the added power supply to turn on. BIOS ROM will detect an unsupported power supply installation. BIOS ROM will halt at POST with a failure message and will light the appropriate LED. The LED will reset when the unsupported supply has been removed and system is restarted. Common-slot power supplies are hot-pluggable/hot-swappable on ProLiant servers under the following conditions: The server must already be configured with redundant power supplies. The removed and replacement power supplies must be of the same type (same part number). For all other situations, the ProLiant server should be powered down before a power supply is removed or installed. 10

Conclusion The common-slot power supply bay allows over 90% of the ProLiant server line to use 80 PLUScertified power supplies. By using IT equipment that supports common-slot power supplies, IT administrators can reduce inventory and energy consumption costs and reclaim data center power capacity. For more information For additional information on topics discussed in this paper refer to the resources listed below. Resource description New generation HP servers HP energy efficiency site HP Power Advisor utility Power Basics for IT Professionals technology brief HP Thermal Logic technology Web address http://h71028.www7.hp.com/enterprise/us/en/messaging/fe ature-servers-newproliantg6.html?jumpid=reg_r1002_usen http://h20219.www2.hp.com/services/us/en/consolidated/da tacenter-energy-efficiency.html?jumpid=reg_r1002_usen http://www.hp.com/go/hppoweradvisor http://h20000.www2.hp.com/bc/docs/support/supportmanu al/c01234421/c01234421.pdf http://h18004.www1.hp.com/products/blades/thermallogic/?jumpid=reg_r1002_usen 80 PLUS program http://www.80plus.org Call to action Send comments about this paper to TechCom@HP.com. 2009 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. 80 PLUS is a registered trademark of Ecos, Inc. TC091110TB, November 2009 11