Sun Fire E6900/E4900 Systems Site Planning Guide

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3.1 Environmental Requirements

The design of your environmental control system--such as computer room air-conditioning units--must ensure that intake air to the server system complies with the limits specified in this section.

To avoid overheating:

• Guard against directing any warmed air toward the bottom of the cabinet or standalone server.
• Guard against directing warmed air toward the server access panels.

The air intake screens act as electro-magnetic interference (EMI) and radio frequency interference (RFI) filters, stopping both EMI and RFI emissions from the system. These screens are a honeycomb-type screens, which also collect and trap dust and debris particles.

The Sun Fire E6900/E4900 systems have been designed for maximum availability. Air intake screens can be cleaned or changed without the need to power off the system.

The Sun Fire E6900/E4900 system's air intake screens require periodic inspection and cleaning. To prevent restricted airflow and possible equipment failure, the air intake screens should be inspected for debris and trapped particles every three months of operation. The level of debris found on the screens and surrounding area should be considered in the decision of when to remove and clean the air intake screen.

The environmental limits for Sun Fire E6900/E4900 systems are listed in Environmental Limits for Sun Fire E6900/E4900 Systems.

The operating environmental limits in Table 3-1 reflect what the systems have been tested to, in order to meet all functional requirements. The optimum operating condition in Table 3-2 is the recommended operating environment. Operating computer equipment for extended periods of time at or near the temperature or humidity extremes is known to significantly increase the failure rate of hardware components.

3.1.1 Ambient Temperature Recommendations

The ambient temperature range of 70°F to 74°F (21°C to 23°C) is optimal for system reliability and operator comfort levels. Most computer equipment can operate within a wide temperature range, but a level near 72°F (22°C) is desirable because it is easier to maintain safe associated relative humidity levels at this temperature. Operating in this temperature range provides a safety buffer in case the environmental support systems go down for a period of time. Though individual standards vary slightly, 70°F to 74°F (21°C to 23°C) should be used as an optimal recommendation.

3.1.2 Ambient Relative Humidity Recommendations

The ambient relative humidity levels between 45% and 50% are the most suitable for safe data processing operations. Under certain circumstances, most data processing equipment can operate within a fairly wide environmental range (20% to 80%), but the optimal goal should be between 45% to 50% for several reasons:

• The optimal range helps protect computer systems from corrosivity problems associated with high humidity levels.
• It provides the greatest operating time buffer in the event of environmental control system failure.
• This range helps avoid failures or temporary malfunctions caused by intermittent interference from static discharges that occur when relative humidity is too low.

Electrostatic discharge (ESD) is easily generated and less easily dissipated in areas where the relative humidity is below 35%, and becomes critical when levels drop below 30%. The 5% relative humidity range may seem unreasonably tight when compared to the guidelines used in typical office environments or other loosely controlled areas, but it is not so difficult to maintain in a data center because of the high efficiency vapor barrier and low rate of air changes normally present.

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3.2 Facility Power Requirements

To prevent catastrophic failures, the design of your power system must ensure that adequate power is provided to your Sun Fire system. Use dedicated AC breaker panels for all power circuits that supply power to your system. Electrical work and installations must comply with applicable local, state, or national electrical codes.

Provide a stable power source, such as an uninterruptible power system (UPS), to reduce the possibility of component failures. If the computer equipment is subjected to repeated power interruptions and fluctuations, it is susceptible to a higher component failure rate than it would be with a stable power source. Every Sun Fire system requires its own customer-supplied circuit breaker and AC receptacle for each power cord.

Each power cord will also supply your system with proper earth ground. Sun has tested both Sun Fire E6900 cabinets and Sun Fire cabinets for radiated and conducted emissions and have determined there is no difference in emissions with or without a ground strap grounding the cabinets. No additional earth grounding is necessary but, it may be added if desired.

The Sun Fire E6900 system has dual Redundant Transfer Units (RTUs) with four Redundant Transfer Switches (RTSs). Two totally independent AC power sources are needed for input power redundancy. The AC power sources must be derived from independent power company utility feeds and Sun recommends that each be backed up with an on-line UPS. The power sources are not independent if they are only distinguished by having separate circuit breakers. One RTS hooked to an AC power source and the second RTS hooked to a UPS that is connected to the same AC power source is not supported because when the UPS is by-passed for maintenance both RTSs will be hooked up to the same source. If both RTSs are hooked to one utility feed then both lines must be backed up with on-line UPSs to ensure input power redundancy.

• In configurations with two RTU assemblies and two independent AC power source there will be four cables to connect, two on the front, and two on the rear of the system (FIGURE 3-1).

• In configurations with one RTU assembly and two independent AC power sources there will be two cables to connect, both in the rear of the system (FIGURE 3-2).

• In configurations with two RTU assemblies and one AC power sources there will be two cables to connect, one in the front (on the left), and one in the rear of the system (on the left) (FIGURE 3-3).

Caution - Connecting the alternate RTS units to outlets that use the same power source as the default RTS units is not supported and will adversely affect reliability.

FIGURE 3-3 Two RTU Assemblies and One AC Power Source

• In configurations with one RTU assembly and one AC power sources there will be only one cable to connect (in the rear of the system on the left) ().

Caution - Connecting the alternate RTS unit to an outlet that uses the same power source as the default RTS unit is not supported and will adversely affect reliability.

FIGURE 3-4 Sun Fire Cabinet for Sun Fire E4900 Configuration: One RTU Assembly and One AC Power Source

Every piece of support equipment requires its own customer-supplied circuit breaker and receptacle(s).

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3.3 Electrical and Cooling Specifications

This section provides guidelines and requirements for cooling your Sun Fire systems. For electrical and cooling specifications, see the following tables:

• Electrical Specifications for the Sun Fire E6900 Cabinet for the Sun Fire E6900 system
• Electrical Specifications for the Sun Fire E4900 System for the Sun Fire E4900 system
• Table 3-5 for the Sun Fire cabinet

Be aware of the following system cooling rules and guidelines:

• The room should have sufficient air-conditioning capacity to support the cooling needs of the entire system.
• The air-conditioning system should have controls that prevent excessive temperature changes.

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3.4 Thermal Guidelines for Sun Fire
E6900/E4900 Systems

These guidelines are intended to assist those who would install the Sun Fire
E6900/E4900 systems at the end users' site. These guidelines address cooling issues only.

It is the ultimate responsibility of the end user to ensure that the environment in which these systems are mounted meet the following:

• All systems specifications
• Safety requirements specifications

3.4.1 Conditions

• Any systems mounted in a rack with Sun systems must have front-to-back cooling (no side to side).
• The front of the cabinet should not be facing, nor be in the path of, the exhaust air from any other systems or cabinets.
• It is recommended that the cabinet allow 0.188 cubic meters per second (600 cubic feet per minute) of exhaust air out of the cabinet by way of the exhaust fans located at the top of the cabinet.
• The cabinet must allow for airflow to enter from the front and exhaust to the rear. Do not use a closed cabinet that prevents airflow into the front and out of the rear of the enclosure.
• A cabinet front filler panels must be attached so that no gaps appear between panels and between the panel and the system. If the panels cannot completely fill in the area above the system, make sure the gap appears at the top of the cabinet, away from the system. Cabinet front panels prevent hot air that is expelled from the rear of the cabinet from reentering the system from the front.
• Multiple systems in the same cabinet must be mounted as close together as possible without air gaps in between, to avoid exhaust air recirculating back into the front air intake.
• All systems must be mounted in the lowest possible locations within the rack, to prevent the cabinet from tipping over.

FIGURE 3-5 Sun Fire E6900 System Air Flow--Front and Rear

FIGURE 3-6 Sun Fire E4900 System Air Flow--Front and Rear

^{1 (TableFootnote) One power cord for each RTS installed. Minimum required is two and maximum is four.}

^{2 (TableFootnote) One receptacle type for each power cord installed.}

^{3 (TableFootnote) One power cord for each power supply installed. Minimum required is two and maximum is three.}

^{4 (TableFootnote) One receptacle type for each power cord installed.}

^{5 (TableFootnote) One power cord for each RTS installed. Minimum required is one and maximum is four.}

^{6 (TableFootnote) One receptacle type for each power cord installed.}

Sun Fire E6900/E4900 Systems Site Planning Guide

817-4117-14

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