如何用EXCEL解决数据中心配置问题（题目中的图在附件）

dorische2006

Background
Frank Lee, a renowned dentist, is the chairman of the China side of a Fortune 500 global company, Advanced Biomedical Company (ABC). In his last year of service before retiring, he has received an executive memorandum from the company headquarters in the United States. The memorandum informs Frank that all the China branch offices are to be closed, and their corresponding IT resources are to be consolidated into the Shanghai main office building, Westley House. The instructions strongly indicate that a data centre should be built to accommodate these business changes.

Westley House is a seven-storey building that was constructed in the late 1980s from a combination of steel frame, brick, and concrete. It is going to be completely refurbished and the ground floor has been selected to accommodate the new data centre; with a gross area of approximately 550m2, of which about 240m2 has been earmarked for the computer room. The other six floors of the building also have gross areas of around 550m2, and will eventually accommodate those staff and facilities that will be moved in
from the closing branch offices located in other major cities within China.

Frank has no idea what a data centre is and has limited knowledge on IT and communications technologies. An old friend of his though, tells him that since his company had a data centre built, all of their IT problems have just about disappeared  and they now rely on their data centre completely. Frank gets the feeling that this is the way to go with the IT side of the business, and he should ensure that all is made right before his hands over control of the Chine business activities to his successor. However, whilst playing a round of goal of his club during one weekend, the sales director of a large French co-location data centre and web-hosting company bribes Frank’s caddy to ensure that they arrive at the 14th tee at the same time and play the remaining holes together. The Sales Director mentions that a company like ABC could save millions per year by doing without their own dedicated data centre and by outsourcing everything to a company like his. All that would be needed would be two optical fibre lines in Westley House and a one million dollar a year contract. Frank is now more confused than before, but he instinctively know that this all sounds too good to be true. Nevertheless, he makes a mental notes to bear this proposition in mind.

Back to Westley House, Frank instructs David Chan, Chief Operating Officer, to report on the future plans and costs associated with the consolidation project, and particularly the new IT strategy. He tells David that he needs to have firm facts and figures before deciding whether to consolidate into Westley House or whether to outsource to the collocation data centre company.

Like Frank, David is not really an IT person, but he has just promoted Teddy Yuen, a whiz kid from one of the branch offices to the newly created post of Chief Information Officer. Teddy has made his name by becoming a Cisco and Linux guru rather than as a polymath Project Manager, even less so in data centre building out. David understand that help is needed in order to meet tight timeline set by Frank.

Data Centre Capacity Assessment
In order to understand more about data centre build-out, David subscribes to newsgroups that relay data centre information and discussion to all subscribers. One of the discussion threads catches David痴 attention as he believes an important issue has been overlooked and might lead to long-term inefficiency of the new data centre. The thread brings out the importance of considering the growth of the business and other factors that may have an effect on the data centre build-out in particular the capacity of the data centre given the various growth factors for the next five years.

Teddy proposes to David to carry out an assessment on the data centre capacity. The pressing decision is whether the proposed data centre to be built on the ground floor of Westley House would be sufficient for the business need in the next five years. David agrees with the proposition and therefore approaches Sysco to perform a capacity assessment of the proposed new data centre. He believes that such information is a critical factor in determining whether to outsource to a co-location data centre company or to build the new data centre on the ground floor of Westley House.

After a couple of weeks, ABC and Sysco successfully reach an agreement on the consultancy engagement. The objective of the consultancy service is to answer the question of whether the new Westley House data centre would be able to sustain the organic growth of the business in the next five years using the current IT infrastructure as the baseline for growth projection.

Data Centre Layout
Sysco proposes the following data centre layout after a site visit of Westley House and
an initial discussion with the IT teams of the headquarters and conference calls with the
IT teams of various branch offices.

Figure 1 Proposed Westley House Data Centre Layout
Racks in grey are not server-deployable, for example, the rack A00 is reserved for network devices as the end-of-row design is adopted in the proposed layout. C20, C21, and C22 are reserved for SAN storage and are also not server-deployable. D00 and D01 are reserved for tape systems and they are similarly not server-deployable. In other words, servers can only be assigned to the racks in green during the capacity assessment exercise.
Data Centre Networking
Sysco has assured ABC that their initial proposition is technological feasible in the sense that there will be sufficient redundancy to ensure high availability of the network, sufficient connectivity will be available between racks and devices to be housed in the racks, and sufficient bandwidth will be installed to address the need of the server farms. In short, the capacity assessment should perceive the network infrastructure as no bottleneck for future growth as long as the earmarked racks are made available to house network and associated devices & equipment.

Data Centre Rack Layout
Even though power and cooling are often problematic when it comes to data centre growth, Teddy reckons that the primary concern for ABC would be space (to be precise rack space) since the building is originally decided for industrial use with ample power provision and very solid floor loading capacity. The followings are the key design decisions for the proposed Point of Delivery (POD) design.

End-of-row cabling design for all POD designs
Top-of-rack is also used for high density POD’s such as POD for blade servers

Sysco also provides the following technical information related to the deployment of rack space.

Table 1 Technical Parameters & Settings

Figure 2 POD Supporting Rack-Mount Servers (Example)

Figure 3 POD Design Supporting Blade Servers (Example)

While Sysco works on the technical side, Teddy has a number of discussions with senior
including Frank to project the commissioning of business services, decommissioning of existing business services as well as the organic growth of the business services that will continue to run in the next five years. With the help of the IT teams in the branch offices, Teddy is able to translate the business projection into IT projection as shown in the table below.

Table 2 Business Parameters & Settings

A list of all existing servers to be assigned to the racks is given in a separate Microsoft Excel spreadsheet. Sysco will base on the current server inventory to develop an optimal assignment to the existing racks and then project the impact of business growth to the data centre on a year-by-year basis.

Point-of-Delivery (POD) Design
Sysco proposed the following POD designs to accommodate the rack-mount servers and blade servers that are expected to be housed in the new data centre.

Table 3 Deployable POD Designs
Questions
You should assume your team representing Sysco to carry out the capacity assessment. The following questions are to be addressed upon the completion of the capacity assessment.

Question 1. Develop an approach to tackle this problem. You may consider taking power and cooling into the model. Provide a description of the approach to convince ABC management of the proposed approach.
Question 2. State clearly the technique the team intends to use to implement the approach. Describe any foreseen problems and explain how the problems are to be addressed.
Question 3. Develop a model using (partly) Microsoft Excel Solver to perform the allocation of servers to racks such that space is optimized. In other words, the allocation must be optimized in such a way that minimal space is deployed.
Question 4. Develop a model using (partly) Microsoft Excel Solver to capture the notion of growth and then the subsequent changes to the rack space from the second to fifth years.
Question 5. Draw a conclusion based on the data provided by the models used in Question 3 and Question 4. Also, explain in detail any shortcoming of the proposed approach and if/how they can be addressed to improve the quality of the outcome.