[. . . ] Mac OS X Server Xgrid Administration and High Performance Computing For Version 10. 5 Leopard Apple Inc. © 2007 Apple Inc. All rights reserved. The owner or authorized user of a valid copy of Mac OS X Server software may reproduce this publication for the purpose of learning to use such software. No part of this publication may be reproduced or transmitted for commercial purposes, such as selling copies of this publication or for providing paid-for support services. Every effort has been made to ensure that the information in this manual is accurate. [. . . ] For example, you might need one or more uninterruptible power supplies (UPSs) to provide backup power to key cluster components. Another requirement might be a physical security system to protect the cluster from unauthorized access to sensitive information. Infrastructure requirements are divided into the following subcategories:  "General Hardware Requirements" on page 68  "Power Requirements" on page 68  "Cooling Requirements" on page 69  "Weight Requirements" on page 70  "Space Requirements" on page 70  "Network Access Requirements" on page 71 General Hardware Requirements To set up a cluster, you should have the necessary hardware infrastructure in place. This includes:  Racks  Electrical power  Cooling system  Network access points and switches Power Requirements When setting up the physical infrastructure for your cluster, consider the following power consumption figures:  Rated power consumption. This figure represents the maximum power consumption of a given system's power supply. This figure represents the typical power consumption of a server under normal operating conditions. Note: This section focuses only on the rated power consumption figure because it guarantees that your circuit won't be overloaded at any time--unlike the typical power consumption figure, which doesn't protect your circuit from abnormal surges in power consumption. 68 Chapter 8 Identifying Prerequisites and System Requirements To obtain power consumption figures for cluster nodes, see the following articles on the AppleCare Service & Support website:  Article 86694, "Xserve G5: Power consumption and thermal output (BTU) information, " at www. info. apple. com/kbnum/n86694  Article 75383, "Xserve: Power Consumption and Thermal Output (BTU) Information, " at www. info. apple. com/kbnum/n75383  Article 86251, "Xserve (Slot Load): Power Consumption and Thermal Output (BTU) Information, " at www. info. apple. com/kbnum/n86251  Article 304887, "Xserve (Late 2006): Power consumption and thermal output (BTU) information, " at www. info. apple. com/kbnum/n304887 Although the rated current load covers your cluster nodes, you must also consider the power consumption of other devices connected to your circuit. For large clusters, speak with an Apple Systems Engineer to determine the correct power infrastructure. For information about Apple consulting services and service and support plans, see the Apple Server Service and Support website at http://www. apple. com/server/support. WARNING: The formulas in this section help you estimate your power requirements. These estimates may not be high enough, depending on your configuration. For example, if your cluster uses one or more Xserve RAID systems, or other thirdparty hardware, you must include their power consumption requirements. Cooling Requirements It's very important to keep your Xserve computers running at normal operating temperatures (see www. apple. com/xserve/specs. html). If your servers overheat they will shut down and any work being done will be lost. You can also damage or shorten the life span of your servers by running them at high temperatures. To obtain thermal output figures for cluster nodes, see the following articles on the AppleCare Service & Support website:  Article 86694, "Xserve G5: Power consumption and thermal output (BTU) information, " at www. info. apple. com/kbnum/n86694  Article 75383, "Xserve: Power Consumption and Thermal Output (BTU) Information, " at www. info. apple. com/kbnum/n75383  Article 86251, "Xserve (Slot Load): Power Consumption and Thermal Output (BTU) Information, " at www. info. apple. com/kbnum/n86251  Article 304887, "Xserve (Late 2006): Power consumption and thermal output (BTU) information, " at www. info. apple. com/kbnum/n304887 Chapter 8 Identifying Prerequisites and System Requirements 69 Consider the thermal output of other devices, such as the management computer, Xserve RAID systems, monitors, and other heat-generating devices used in the same room. As always, consult with your system administrator to determine the necessary level of cooling that your cluster and its associated hardware require for safe and effective operation. Weight Requirements For Xserve and cluster node weight information, see the Apple Xserve website at www. apple. com/xserve. Also include the weight of the rack if you're bringing in a dedicated rack, and the weight of other devices used by the cluster. If you mount cluster nodes in a rack with casters, set up the rack where you'll keep the cluster and then mount the systems. In addition, vibrations caused by moving your cluster long distances when racked might damage your hardware. After determining weight requirements, consult with your facilities personnel to make sure the room where the cluster will be installed meets the weight requirements. [. . . ] In the small office or home, the term router often means an Internet gateway, often with Network Address Translation (NAT) functions. Although generally correct, the term router more properly refers to a network device with dedicated routing hardware. server A computer that provides services (such as file service, mail service, or web service) to other computers or network devices. A protocol that allows client computers to access files and network services. [. . . ]