Server fans: what they are, how they work
The main function of server fans is to maintain the temperature of the server system within normal limits. Since servers operate continuously, they generate a large amount of heat. If this heat is not controlled, it can lead to emergency situations, such as CPU overheating, improper operation of RAM, etc. All of these can cause server system malfunctions and result in significant losses of important data.
Server fans play a key role in maintaining the temperature at an optimal level. They operate at high speeds to ensure sufficient airflow within the server system, thereby cooling it. Most server fans are designed to operate at different speeds, which significantly enhances their efficiency. This means that when the server system is under load, the server fans operate at higher speeds to increase cooling, and when the load is light, the speed decreases. These devices are equipped with temperature sensors that allow the speed of the fans to be regulated depending on the current temperature in the system.
Types of Bearings Used
Various types of bearings can be used in server fans depending on operating conditions and performance characteristics. Each type of bearing has its own features and advantages, so the choice of a particular type of bearing is justified depending on specific requirements for the fan.
1. Hydrodynamic Bearings
Hydrodynamic bearings are based on the use of oil or liquid to lubricate the shaft inside the bearing.
During fan operation, the liquid creates a thin layer between the shaft and the inner surface of the bearing, which reduces friction and wear.
2. Ball Bearings
Ball bearings are used when high rotational speeds are required. These bearings consist of an inner and outer ring, balls, and a cage. This type of bearing has a lower lifespan compared to other types, but it also allows for higher speeds.
Choosing the suitable type of bearing for a server fan depends on the specific operating conditions, as well as the necessary performance characteristics. Hydrodynamic bearings provide excellent work at low rotating speeds, while ball and roller bearings are used in conditions of increased rotating speed and constant high load. Server fan developers usually choose a bearing, taking into account many factors, such as performance, power consumption, and vibration.
Fan Power Consumption
Fan power consumption in servers is an extremely important aspect in the design and operation of servers. The reason for this is that fans are critical components of a server, responsible for cooling its components, which in turn affects such parameters as reliability and performance. The total percentage of energy consumed on fans in servers can range from 5 to 30%, depending on their configuration, size, and temperature regime.
For an average 1U, 2U, 3U, and 4U server, it can be assumed that the percentage of energy consumed by fans will range within the following limits:
- For a 1U server: 20 to 30%
- For a 2U server: 15 to 20%
- For a 3U server: 5 to 10%
- For a 4U server: 10 to 20%
These figures are approximate and may vary depending on different factors, such as server design, components used, and cooling system settings. As can be seen, the 3U size is optimal in terms of energy efficiency.
Dual Fans
When only one fan is used in a server, it can be the only point of failure in the cooling system. If the fan fails, it can lead to overheating of the server components and potential loss of important data.
Dual Fans
When only one fan is used in a server, it can be a single point of failure in the cooling system. If the fan fails, it can lead to overheating of server components and potential loss of important data.
Dual fans solve this problem because each fan works independently and in the event of one failing, the other maintains the functionality of the cooling system.
Additionally, dual fans provide more effective cooling as they create greater airflow compared to a single fan. This is particularly important for high-performance 1U servers that generate a lot of heat but require high pressure for ventilation due to their compact layout.
Dust Filters
Dust filters are typically not used in servers because they can reduce the cooling system's performance and reliability. Dust and dirt can accumulate on the surface of dust filters, obstructing airflow through the cooling system and potentially raising the temperature inside the server.
In addition, dust filters can become blocked, necessitating regular cleaning and replacement. This can be a costly and time-consuming process that may result in lengthy server downtime.
Instead of dust filters, server rooms are typically equipped with built-in air filtration systems that can capture large particles of dust and dirt without impeding the flow of air.
Hot Swap Fan Replacement
Hot swap fan replacement allows for quickly replacing broken fans without the need to shut down the whole server. This minimizes server downtime and maintains service availability for users. The inability to hot swap fans may be due to the design of a specific server. For example, some servers may have fans that are located very close to other components, making it difficult to access and replace them without shutting down the server. Additionally, it is worth noting that in modern virtualized computing environments, a regular server is reserved entirely and can be taken out of operation during maintenance without interrupting service.
Largest Server Fan Manufacturers
Among the well-known server fan manufacturers, several companies stand out:
- Delta Electronics - a Taiwanese company that produces a wide range of electronic components for computers, including server fans.
- Nidec Corporation - a Japanese company that is one of the largest producers of motors and fans for computers and other electronics.
- Sunon - a Taiwanese company that specializes in manufacturing fans for computers and other electronics.
Of course, there are many other server fan manufacturers on the market, but these companies have a long history and a good reputation in the industry.
Ron Amadeo
16/03.2023