Access to and the quality of electricity are critically important factors for any business where technologies play an important role. This is especially important in a data center, because servers that are located there serve the business functions of many such companies and continuous system operation is of critical importance (for example, for banks, stock markets, security institutions).
And so, when building, expanding, or improving an existing data center, it is critically important to assess the technology aspects that determine the continuous operation of these centres. Electrical supply is not the only aspect of continuous operation that needs to be kept in mind, however, its significance is paramount, and it is the highest priority for providing continuous and sustainable operation of a data center. Therefore, we will also consider this topic in our blog.
There are many critically important elements for power supply in a data center: arterial or main distributors, backup generators with diesel repositories, continuous feed supplies (UPS), rack outlet blocks (PDU).
Power supply problems can occur for various reasons. These can be disturbances to the operation of technologies, weather conditions, a physical breakage of arterial cables, and many other reasons about which we normally don’t think of. Every interruption of data center operation will essentially affect the work of those businesses for which continuous operation of systems in the data center is of critical importance. And so, maintainers of a data center must plan for secure backup electrical supplies that provide continuous operation even in situations where there are disruptions of electrical supply.
“If you are preparing for TIER certification of a data center or are planning or already designing a TIER level data center, first and foremost, an appropriate backup electrical supply system must be provided. Certifiers do not consider the arterial electrical supply provided by electrical companies to be a primary and secure electrical supply for a data center.”
When talking about a backup electrical supply, there are various levels of solutions known in the industry, for example, a data center can offer backup solutions N+1 and/or 2N.
The concept of the N+1 solution
Every professional data center provides a specific level of backup solutions. And it is only beneficial for potential clients to fundamentally understand how important they are.
Solution N+1 provides that there shall always be backup electrical supply available from diesel generators and UPS. The “N” indicates the number of UPS modules necessary to provide electricity in the volume that is required for the functioning of data center equipment. The “+1″ indicates the additional UPS module (equipment that is in active operation) for providing the necessary electrical power in the event that any of the feed modules stops working. The N+1 solution is relatively secure, but it also has its drawbacks. These include potential disturbances to system operation if, for example, operational problems occur to two UPS devices at the same time or if the overall solution does not provide a complete (100%) backup system, since the electrical supply is provided in a chain where operational interruptions can theoretically occur. It must be said that implementation of the N+1 solution also requires significant competence and experience.
The 2N solution — a completely reserved system
The concept of the 2N solution intends for a completely backed up system that automatically also means twice the amount of equipment. For example, if six UPS modules are required for the operation of data center equipment, then in the 2N case, 12 pieces of UPS equipment will be needed. In the 2N solution, the electrical supply systems do not have any shared critical points for providing operation. This means that any electrical supply problem influences only one piece of equipment, and the other piece of equipment replaces it completely. Such systems must be used in airplanes in order to provide the necessary level of operational continuity. Drawing parallels to this, it can be understood how serious the security issues for data centers are and what level of solutions are used.
The 2N solution is used in critically important facilities (related to state security, armed forces, etc.) and the backup system for this level is compliant with TIER 4 level certification requirements — for data centers that comply with the strictest requirements in relation to its secure operation.
The 2N solution is the most stable alternative. However, it must be remembered that this stability will cost significantly more. If a company does require the 2N backup level for at least a portion of its technologies located in a data centers, then the company can look for a data center that simultaneously provides both solutions (N+1 and 2N), locate its critically important software in the 2N backup section, and implement the N+1 solution for remaining resources.
The decision regarding the provision of the optimal security level and the development of its respective technological solution is individual for each situation and dependent on several conditions — results from assessing risks threatening the operational continuity of a data center, potential client requirements, further planned development of a data center, etc. In any case, if development of a serious solution is being considered (regardless of whether a high level solution for operational continuity is being developed, intending its certification or not), it is recommended to involve experts who are familiar with the design requirements for a certified data center and the main approaches for constructing solutions.
Involving experts can significantly save time and resources for transforming a solution — to adjust a solution for certification requirements, to immediately choose a globally recognised approach to developing an optimal technological design for a data center from the perspectives of sustainability and operational continuity.
It is recommended to choose an expert from a company that works with data center construction and has successfully completed the certification process. It is also recommended that the company employs experts certified by the Uptime Institute who can competently supervise the observance of TIER recommendations and requirements at specific construction phases during the whole project.