I. How to Choose the Right Server Rack
Choosing a deeper rack allows you to install two sets of equipment face-to-face, thus accommodating more devices. This method allows for two rows of equipment to be installed in the rack, one row to be loaded and unloaded from the front door and the other from the rear door. The rack should be adjustable. After calculating the rack space (in "U" or 1.75 inches), you also need to consider the room size. No one wants to find themselves needing to crammed in more equipment shortly after filling the rack.
Once you've purchased and installed the server rack, these extra devices often appear. Therefore, as a basic principle, the rack height should be 20%-30% higher to allow for system expansion. This extra space also improves ventilation for the equipment. For devices mounted on racks, width doesn't need to be considered, as they are designed for rack width. However, for servers and other peripherals that cannot be mounted on racks, width is crucial.
Since the total weight of the equipment is often considerable, you need to choose a rack that can accommodate approximately 1500 pounds; that is, a robust rack with a good load-bearing structure. Inside the rack, the weight of the equipment determines whether to choose standard or weighted sliding brackets, and also dictates the selection of other accessories. Choose a rack that is 100% compatible with all servers and meets or exceeds all OEM/manufacturer Category 3 rack specifications. If you intend to install tower or desktop equipment, sliding brackets and mounting accessories are essential.
Since the installation includes network cables, telecommunications cables, and power cables, hook and loop straps or toothed straps are needed to effectively and orderly secure the cables inside the cabinet. It would be ideal if the cabinet had a cable management module that allowed cables to be directly secured within vertical mounting rails. In either case, the top and side walls inside the cabinet should have sufficient securing loops (to protect the cables), or the cabinet base can be raised to allow for cable routing underneath.
II. Server Rack Grade
Although server racks may look similar, they can be categorized into several types based on their purpose. The rarest are racks for cabling and racks for housing servers. Cabling racks are typically used to house multiple terminal switches, resulting in numerous network cables that need to be routed out. Since it's inconvenient to install a door on such racks, they resemble server racks more closely, and some rack manufacturers refer to this product as cabling racks. On the other hand, server racks for housing servers definitely have doors and locks to protect the valuable equipment inside. Therefore, high-end routers and firewalls are usually placed in these racks.
Take server racks as an example; there are different grades. This type is a standard server rack with a glass door. It has four cooling fans at the top, primarily for ventilation and heat dissipation, providing a good constant temperature environment inside the rack. The bottom of the rack is perforated for ventilation. Servers in the top of this type of rack have excellent heat dissipation, but the heat dissipation for servers in the middle and lower sections is less ideal.
The type of server rack shown above is a relatively high-end server rack. It uses numerous air vents on the front and back doors for ventilation and heat dissipation. As a result, the cool air from the server room air conditioner can be well distributed around each server in the rack, and the overall heat dissipation effect of the rack is good. Moreover, this type of rack uses high-quality materials, is corrosion-resistant and rust-proof, and has a strong load-bearing capacity.
III. Factors Users Should Consider When Purchasing Server Racks
1. Reliable quality assurance
Choosing the right server rack and cabling rack is crucial; even slight negligence can lead to significant losses. Regardless of the brand, quality is always the primary consideration for users.
2. Load-bearing capacity guarantee
As the density of products placed inside server racks increases, good load-bearing capacity becomes a basic requirement for a qualified server rack product. A substandard server rack, due to its poor quality, may fail to effectively protect the equipment inside, potentially impacting the entire system.
3. Temperature control system
The cabinet features a robust temperature control system to prevent overheating or overcooling of the products inside, ensuring efficient equipment operation. Fully ventilated cabinets are available, and fans (with a lifespan guarantee) can be installed. Independent air conditioning systems can be installed in hot environments, while independent heating and insulation systems can be installed in extremely cold environments.
4. Anti-interference and other
A fully functional server rack should provide various door locks and other features, such as high immunity to interference, including dustproof, waterproof, or electronic shielding; it should also provide suitable accessories and installation support to facilitate cabling, make management easier, and save time and effort.
5. After-sales service
The effective services and comprehensive equipment protection solutions provided by the company can bring great convenience to users' installation and maintenance.
6. Power distribution system
How can server racks cope with rising power density? With the increasing trend of high-density IT installations within server racks, the power distribution system becomes a critical factor in ensuring the rack's effectiveness. Proper power allocation directly affects the availability of the entire IT system and is a fundamental element for its effective operation—an issue often overlooked by data center administrators. Due to the increasing miniaturization of IT equipment, the density of equipment installed within server racks is constantly increasing. For example, a single 7U blade server requires approximately 3kVA of power, and a 42U high rack may house up to eight such servers, resulting in a total power demand of 24kVA. This poses a significant challenge to the server rack's power distribution system. Simultaneously, the increase in input and output ports also places high demands on the reliability of the power distribution system.
A well-designed rack power distribution system should adhere to the principles of reliability-centric design, specific design for the rack system, and seamless coordination with the power distribution system. It should also consider ease of installation, intelligent management, adaptability, and ease of operation and maintenance. The rack power distribution system should bring the power source closer to the load to reduce potential points of failure in the power path. Furthermore, it should gradually implement local and remote monitoring of load current and remote control of power distribution, integrating power distribution management into the overall intelligent management system of the data center.
7. Cable Layout
What to do if there's a cable problem? Navigating through towering server racks in a massive data center is difficult enough, let alone quickly locating and repairing faulty lines. The adequacy of the overall server rack solution, and its effective cable management, will become a key evaluation factor.
From the perspective of internal cabling in server racks, today's data centers have higher rack density, accommodate more IT equipment, and extensively use redundant components (such as Foshan electrical appliances and storage arrays). Equipment configurations within racks change frequently, and data cables and physical cables are added or removed at any time. Therefore, server racks must provide ample cable routing, allowing cables to enter and exit from the top and bottom. Inside the rack, cable routing must be convenient and orderly, close to the cable interfaces of the equipment to shorten cabling distances; minimize cable space occupation; ensure that equipment installation, adjustment, and maintenance are not interfered with by cabling; and ensure that airflow for heat dissipation is not obstructed by cables. Simultaneously, in case of a fault, it should allow for rapid location of the equipment cabling.
When planning a data center that includes servers and storage products, we often overlook seemingly minor details like server racks and power supplies. However, these supporting facilities have a crucial impact on system reliability during actual installation and use. In terms of price, server racks and cabinets range from several thousand to tens of thousands of yuan, which is incomparable to the value of the internal equipment. Because the equipment is concentrated within a server rack, there are particularly stringent requirements for its specifications. If these are not carefully considered during selection, the resulting problems during use can be enormous.
IV. Cable Management Techniques
A crucial aspect of server rack organization is cable management, and there are three common cable management techniques:
Waterfall design
This is a relatively old wiring design, and you can still sometimes see it. It adopts the artistic image of "Water Curtain Cave in Huaguo Mountain", with twisted-pair cables hanging directly from the patch panel modules. When neatly distributed, it has a beautiful sense of layering (24-48 twisted-pair cables per layer).
The advantage of this design is that it saves on cable management labor, but it has many disadvantages. For example, the design is easily damaged when installing network equipment, and it may even make it difficult to install the network equipment properly. The weight of each twisted pair cable becomes a tensile force, acting on the back of the module. If the twisted pairs are not bundled before the termination point, this tensile force may separate the module from the twisted pairs after months or years, causing a breakage. If a module in this patch panel needs to be reterminated, maintenance personnel have to reach into the "water curtain" to perform the work, sometimes with dozens of twisted pairs wrapped around them, and because there is no light source in both directions, it is difficult to see clearly during termination.
Reverse alignment
Reverse cable management involves terminating the patch panel modules and testing them before organizing the cables within the server rack. The method involves organizing cables from the modules outwards from the rack while simultaneously organizing cables inside the cable trays. The advantage of this approach is that after testing, re-organizing cables won't be necessary if a single twisted-pair cable fails a test. However, the disadvantage is that because both ends (the cable inlet and the patch panel) are fixed, a large amount of tangled cables will inevitably appear somewhere in the server room (usually at the bottom of the rack). Reverse cable management is typically done manually, relying on visual inspection and manual labor.
The advantage of reverse cable management is that testing is already complete, so there's no need to worry about cable length at the back of the cabinet. The disadvantage is that because both ends of the cables are fixed, there will be numerous crossings, making it very difficult to organize them neatly. Furthermore, there will inevitably be a section of twisted-pair cable that is tangled between the two fixed ends, often located under the floor (for bottom-entry cables) or on the ceiling (for top-entry cables).
Positive line arrangement
Forward cable management involves tidying up the cables before termination on the patch panel. It starts from the cable entry point in the server room and organizes the cables segment by segment until they reach the patch panel modules. Termination and testing are then performed after cable management.
The goal of forward cabling is to: Organize the horizontal twisted-pair cables from the inlet of the server room (or server room network area) to the patch panel cabinet, forming bundles of horizontal twisted-pair cables for each 16/24/32/48-port patch panel. Within each bundle, all twisted-pair cables must be parallel (crosstalk caused by parallel twisted-pair cables over short distances will not affect overall performance because most of each twisted-pair cable is laid in the cable tray and conduit, which is scattered and not parallel), and all bundles must be parallel to each other. Inside the cabinet, each bundle of twisted-pair cables is bent and laid to the back of each patch panel, maintaining parallelism throughout the process. At the back of each module, the corresponding twisted-pair cable is pulled out from the bottom of the bundle, verified, and then fixed to the cable tray behind the module or threaded into the module hole of the patch panel.
The advantage of forward cable management is that it ensures cables are neatly arranged at every point in the server room and prevents cable crossings. However, the disadvantage is that if a cable is damaged during installation, it will fail tests and require re-management. Therefore, forward cable management requires a high degree of confidence in the quality of the cables and the installation process.
The advantage of forward cable management is that the cables are neatly arranged and parallel from the inlet to the patch panel in the computer room (network area of the main computer room or low-voltage room), which is very aesthetically pleasing. The disadvantage is that the installers must have full confidence in the quality of their work, and forward cable management should only be carried out when there is virtually no need to re-terminate the cables.
