Hello everyone, my network worker friend
A few days ago, I told you about the relocation of the computer room, and found that everyone is quite interested in hardware equipment . If you haven't seen it yet, check this: " Don't underestimate, relocating the network computer room requires a lot of attention ."
Most of the technology and industry experience were shared with you before, but this is a bit "hard".
If the work you do is related to server hardware, the concepts of "1U", "2U", and "rack" must be familiar to you.
Hosting, buying servers or renting and using cabinets is actually as important as choosing the right furniture for your own home.
We need to consider the size, quantity and future expansion needs of the equipment.
In today’s article, I will give you a comprehensive science popularization first. What are racks, cabinets, and U? Discuss and discuss together, the key points of purchasing hardware.
Today's article reading benefits: "Manual for Quick Construction and Troubleshooting of Enterprise Networks"
Friends who want to go deep into enterprise network construction and troubleshooting can private message me and send the password "network construction" to get this manual resource.
01 What is a rack?
A rack is a special structure used to install servers.
It is usually placed inside a standard cabinet, so it is also called a "19" rack because it fits this width standard.
The main function of the rack is to provide an orderly, reliable and safe installation environment for the server.
It's the right size to accommodate all functional servers and ensure they are properly powered and ventilated.
Imagine a rack as a room with shelves of various sizes and shapes to hold different things.
In a rack, each server has its own place , like items on a shelf.
The rack also has some special designs, such as adjustable brackets and trays, which make it easy to install, remove, and maintain servers.
The advantage of using a rack is that it can help us better organize and manage server equipment.
By being placed in a rack, servers can be stored more securely and are easier to maintain and manage.
In addition, the rack provides proper cooling and cable management systems to ensure that the servers stay in good condition while working.
Generally speaking, a rack is a structure specially designed for servers and can be placed inside a standard cabinet.
It provides a tidy, reliable and safe environment for us to install and manage server equipment.
This allows us to utilize our servers more efficiently and ensure they are up and running.
02 cabinet ≠ rack
Cabinets and racks are actually two different concepts.
Racks provide vertical mounting space and structural support for equipment.
The cabinet provides more comprehensive functions , including physical protection, cooling and power management.
A rack is a frame structure within a cabinet that supports the installation of equipment.
A cabinet is an overall container containing racks and other components used to store and manage equipment.
It can be used in different places, such as network wiring room, floor wiring room, computer room, data center, etc.
The height of the cabinet is expressed in a special unit of measurement called U.
The height of each U is approximately 4.45 cm (approximately equal to 1.75 inches).
We can think of U as the usable vertical space inside the cabinet .
The equipment in the cabinet, such as servers and network equipment, usually has a standard panel size and is manufactured according to the number of U.
Some non-standard equipment can also be put into a 19-inch cabinet by adding an adapter board.
The common height of the standard cabinet is 42U, and there are other height specifications such as 47U, 37U, 32U, 20U, 12U and 6U.
The cabinet provides a tidy and safe environment, which is convenient for us to manage and install equipment.
Cabinets of different heights can be selected according to needs to meet the installation requirements of different equipment.
03 What is "U"?
Let me tell you more about the "U" just mentioned.
U is a unit representing the external size of the server, and is an abbreviation of unit.
The height of the rack is usually expressed in "U", and each U is 1.75 inches (44.45 mm) high.
Common rack heights include 1U, 2U, 4U, etc. Larger racks can have more Us.
Among the rack server sizes, the common ones are 1U server, 2U server, and 4U server.
The dimensions of these servers are:
1U=4.445 cm
2U=4.445*2=8.89 cm
4U=4.445*4=17.78 cm.
In actual use, 1U or 2U servers are most commonly used.
Because the service provider calculates the fee based on the space occupied by the server, the use of a 1U server is the most space-saving and the lowest price.
But the scalability of 1U server is not as good as that of 2U server.
The number of 1U hard disks can be inserted at most 4 3.5-inch hard disks, and 2U can be inserted with 8 3.5-inch or more. In addition, the number of PCI slots is also different, 1U can have up to 2, and 2U can have up to 6.
Carrier standard cabinets are generally 42U cabinets:
1. Distinguish by width and depth:
The widths are:
600mm and 800mm wide 42U cabinets,
Depths are:
600mm, 800mm, 900mm, 960mm, 1000mm, 1100mm, 1200mm, etc.;
2. According to actual needs:
Except that the actual size is 42U, the width and depth can be customized according to actual needs.
The number of servers placed in a cabinet is limited, and a 42U cabinet does not mean that 42 1U servers can actually be placed in it.
After the server is placed, there must be space for heat dissipation and movement, some space for wiring, and space for other equipment such as switches, firewalls, and monitors.
Therefore, how many servers can be placed in a 42U cabinet needs to be calculated according to the specific equipment.
Let me give you an example of a 42U cabinet equipment layout diagram.
So the question is, how many server devices are generally deployed in a cabinet?
The number of servers deployed in a cabinet requires consideration of many parameters, such as physical parameters such as server volume, power consumption, and heat generation.
It is also necessary to consider the power supply, cooling, and load-bearing parameters of the cabinet, and how to determine how many servers can be deployed.
When making a decision, you can refer to the key parameters :
1. Reservation: Reserve 1U between each device for heat dissipation, reserve the position of the switch, and consider the position of the PDU.
2. Generally, redundant 10KW power supply is provided, and the static load capacity is not less than 1200kg (determined according to the construction parameters of the computer room).
3. Under the premise of not over-charging, the cumulative number of equipment U in a cabinet generally does not exceed 26U per cabinet, the number of full 1U equipment generally does not exceed 16, full 2U equipment generally does not exceed 12, and full 4U equipment generally 4 to 7 tower.
04 Choose the right racks and cabinets for your data center
As IT business demands continue to grow, IT load becomes increasingly unpredictable.
In fact, you can perceive that even if the power per rack is increased, data center density can also improve power efficiency by reducing the overhead of equipment.
However, the complexity of the data center ecosystem grows with density.
You need a well-designed, complete infrastructure for efficient management and flexibility.
The racks and cabinets that make up the computer room infrastructure should be the starting point of any high-density data center strategy.
01 Pay attention to the rated load of the unit
As the equipment installed in the cabinet increases, the rated load of the unit becomes important.
Cabinets connected to the data center must have a static load rating of at least 3,000 pounds.
The rolling load rating tells you how much weight the cabinet can hold while it's being moved.
If the equipment is deployed at the rack level, which is stacked by a system integrator and shipped to your site, you need to look at the shipping load rating.
All load ratings should be tested and verified by a reputable third-party laboratory.
02 How to set up the space of the cabinet?
Cabinet space is another important consideration.
Even though you want to maximize the space in your data center, the cabinet should still be wider and deeper than the equipment it's going to house.
Provides room for PDUs, cable management, and other accessories, while also leaving room for airflow.
There should be fixed racks on both sides of the server cabinet to place the PDU and line management equipment respectively.
The front and rear of the cabinet for network connection equipment should have fixed brackets to accommodate patch cords and other wiring , including internal wiring management.
03 It is critical to build an optimal environment for equipment
Proper racks and cabinets should provide cooling and airflow management to ensure an optimal environment for equipment while keeping power consumption in check.
The greater the heat load, the greater the need for higher levels of door openings to maximize gas flow.
Cabinets should be compatible with hot-aisle or cold-aisle containment systems , providing shrouded panels and baffles to ensure proper air flow around equipment.
You should also consider rack-based cooling , which will result in a fully enclosed system that provides the shortest possible path for airflow to reach the equipment.
04 How to do access control?
Rack-level access control complements data center security measures.
Locked doors provide the most basic level of protection, but networked electronic access control has a range of benefits.
In addition to preventing unauthorized access, these systems also provide an audit trail of all access attempts for compliance and emergency response.
A networked system should be able to operate and manage all cabinet access from a single web page.
In the end, it's really important to find a solution provider who can meet your various needs for racks and cabinets.
It is best to simplify the installation process, speed up the deployment process, ensure that various parts of the data center infrastructure are compatible with each other, provide customized solutions, and provide consulting, design and landing services.
Finishing: Lao Yang 丨 10-year senior network engineer, more network workers to improve dry goods, please pay attention to the official account: Network Engineer Club