DataCenterPro

Tuesday, 13 January 2015

DataCenter Procurement – When to Buy New?

By now, we have seen the building blocks of datacenter like Racks, Cables, Power, Cooling, etc; we have also learnt about its different aspects including how to Managing your Datacenter. It’s time for us to see other components of its life cycle. In this article, we will go through a different view upon planning and procuring datacenter components.

Before we start.. Welcome Back! I have been busy with holiday season, friends and family for a while so couldn’t contribute to my own blog; well its never too late. Okay.. Lets get back to business.

Overview

Most of the organization having in-house datacenter follows a common mission statement: “To Facilitate the Hardware Availability for Data Center Operations & Efficient Utilization, for the Purpose of Business Continuity with less TCO & More ROI.”. I assume most of you know about the DataCenter Life Cycle Management and the activities involved in it. I am not an expert, but I tried to give my view on DataCenter Life Cycle and Management Framework below:

If we focus on the inner most ring of this framework, we can find the core activities in Datacenter Lifecycle i.e. Analyze, Design, Plan, Procure and Deploy. Analysis happens at very initial stage where we collect information; we hear the Voice of Customer and convert that into requirements. Once you have all the requirements, we need to size the environment accordingly and create a high level design of how things will be deployed or how components will integrate or talk to each other. Later comes the most hectic part of this life cycle. Upper Management, off course, cares about mostly the money. As we have traditionally heard about our AIM for IT Managements:

· The Reduce the Total Cost of Ownership (TCO)

· The Increase the Return of Investments (ROI)

Challenge comes, how to achieve it? I have done multiple projects on IT cost optimization in my past experience, I will be sharing one of them in this article.

Applying Lean Six Sigma Methodology

In Lean Six Sigma, I have learnt about problem solving and improvements via DMAIC process i.e. Define Measure Analysis Improve and Control. Now going back to the problem that we all are facing with High Cost, I tried to use Fish Bone technique to give an overview of how we are getting High Cost in IT Operations in DataCenter. Below is my very basic analysis of high cost, off course, there are multiple branches, pros and cons for every consideration, but like I said, this is just an overview to help you understand where I am coming from.

If you notice, under Money; Annual Maintenance Cost (support) and Procurement are the two major contributors to Operational Expenses and Money expenditure for every environment. Now, I am sure you might have head How Virtualization makes your life easy with features to bring in like Centralize Management, Less support cost etc, so I am not touching on that. However, Lets talks about how we can reduce cost during procurement itself considering virtualization and other techniques.

Legendary Procurement Process “As Is”

Below is the “As is” procurement workflow followed in usually in every organization.

Now, as you can see there are multiple flaws with this process:

• There is No check on optimized usage of existing hardware before new procurement

• There is No check on timelines of usage of New hardware to be procured.

• There are No Guidelines available to choose the Right Hardware for project.

• There is No check if Virtualization can avoid procurement

• Methodology to Track the current role, usage & future plan of Data center hardware is Missing

• Unplanned procurement leads to wastage of CAPEX & OPEX Budget.

Now to make it better, we need first put in our thoughts to Identify the need – what you really want?

Do I need More Hardware in my Environment?
Does present solution meet my needs?
Do I have Areas of Improvement?
Do I have 100% Utilization of Existing Resources?
Am I buying Hardware as per the Roadmap?
Do I need to Invest to Manage existing Resources?
Do I need Business Continuity or Data Availability?
Do I have enough Hardware to Meet the Dynamic Needs?
Do I Track the Usage of Existing Hardware?

New Approach

Definitely, before we proceed with procurement, we need to identify what we have and analyze what we need. Now, let me introduce you a new way of procurement:

You can call it a process or decision tree for “When to Buy”, whichever way its easy for you to integrate with your own environment. I understand its not easy to Bring Change in an organization but when people have common motive, its easy to drive atleast. As you can notice, it highlights the checkpoints where you can think – Can I Avoid Procurement?

Check if free hardware is available
Check if hardware require immediate deployment
Check if free hardware is available during required timeline
Check if free hardware is available in other section, Biz-IT or Partners
Check if server required can be virtual server, if No, Why? verify from TC
Check if storage connectivity would be required.
Check if dedicated path is required for Server

If No, Raw Device Mapping with Virtual Machine can be used
If Yes, VMDirectPath can be used (VMware Technology, similar is available for Microsoft Hyper-v as well)

Check if Simulators can be used

To understand it better lets highlight the changes into sections:

1. The Asset Management - Inventory and Audits: collect your existing hardware inventory and perform audits for its usage and health. This will help in doing projections and planning well in advance.

2. Usage Tracking: With available reports, find out if there is any free hardware or capacity available for deployment. Usually DataCenter Life Cycle Managers have this information.

3. Shared Resources: At times the resources can be shared or can be released in case of Test & Dev environment. Another example is of Public Cloud Hosting.

4. Virtualize: Check the possibility if it can be virtualized. I consider most of the environment already have virtual infrastructure which may or may not have capacity for hosting new VMs. In case you don’t have capacity, rather investing in buy new physical server, invest in increasing the capacity for existing virtual infra and share its resources. You can also go Hosting services these days offered by many vendors.

Well, that was just an overview, but there are many aspects of saving cost. However, to start with, this approach might save some initial investment itself. Why to optimize later when you can cut cost in initial stage, right?

Any more questions? please write back or comment here. There are more things to share..

Request you to join my group on Facebook & LinkedIN with name "DataCenterPro" to get regular updates. I am also available on Tweeter as @_anubhavjain. Shortly I am going to launch my own YouTube channel for free training videos on different technologies as well.

Happy Learning!!

Monday, 15 December 2014

DataCenter 101 - Documenting DataCenter - Make it Visible

By now we had an Overview of DataCenter; we learnt about Racks, Cables and its labeling too. We will go in-depth about few concepts for Power, Cooling, and HVAC in future along with learning technologies like Blade Enclosures, Virtualization and SAN Storage. But first, since now you might notices what you have in your datacenter, lets capture it first. Documenting your datacenter is the most important phase in your datacenter deployment. It’s important when it comes to Managing your Datacenter.

I have seen people capturing Server Implementation Plans (SIP), Network Implementation Plans (NIP) and Standard Operation Procedures (SOP) for New Deployments, but where is the mapping of this information to actual physical deployments. You may an inventory available with you where you have your rack location against your server/storage/switch equipment, but can visualize your datacenter with that? In a way that I give you the information in excel sheet, and you are new to your company and something goes wrong; now I need your assistance to walk-in to the datacenter and check if the cables connections are fine for a particular setup; so you think you can do that with your current available information? Imagine the time you would lose in tracking it even though you have labels in your datacenter. You know time=$$$ right!! So I suggest, invest sometime in making it how you visual it so that you don’t have single point of failure in absence of people who deployed it.

I believe you are convinced by now that why you need to create datacenter documentation. So let’s talk about what need to be captured (suggested) in this document and what you need for that.

To Be Captured:

1. Overview: It’s like a summary of your datacenter, how it looks. I prefer to mention who designed the document and who owns the document along with who reviewed and approved the document as important information to be mentioned in the beginning itself. It’s give a level of confidence on the document. Like I mentioned, this shows how it looks don’t jumble the position of equipment, racks and their location within. It should be like a photo as it looks.

2. Power: I believe it’s a good practice to mention the current operating power and max requirement specification based on engineering design. You would need assistance of your local maintenance guyz to measure operating power in peak hours. Suggest you to take max noted in one week or you can take average as well. As per my experience, usually 3 phased power is used in a datacenter. In this example, R-Red, B-Blue and Y-Yellow is named as three phases and its consumption across a rack. You need to notice on the total power available in a circuit and its consumption.

3. Network LAN: Next comes the Network connections, ISL and bandwidth usage presentation. I would suggest to make one more sheet to represent the IP subnet used in individual racks along with number of ports. This comes handy when doing a root cause analysis in case of network break-down.

4. Storage SAN: Storage connections are usually tricky and gets messy if your datacenter goes scalable on-demand without proper planning. It is suggested to give a visualization of how storage connections are made across racks and then a logical presentation of ISL connections. Its comes handy when troubleshooting performance issues.

5. Server Connections: I always to show case a cable connection within a rack and it should be pasted or available as reference material with critical deployments. Imagine you had to remove cable connection for maintenance or replacement of any components and cables get swapped? This is suggested for deployments in a rack.

6. Setup Configuration: This is a brick level logical presentation of your deployments; where you map how your physical infra (Server, Storage, Network and most important Applications) exist in different layers. I have seen this in Server Implementation Plans (SIP) but not sure if everyone provide the detailed information about the deployments every-time like physical rack information, Management IP etc. Sharing some examples below:

7. Contact Information (Disaster Run-Book): This section should always come either first or last, preferred last though. This should mention the on-call IT team members name and contact information along with respective areas of expertise like Windows, VMware, Server, Storage, Network or domain of ownership like Power, Cooling, Space etc. This comes handy and becomes a reference in case of Disaster. You can also mention Vendor support information like Contract IDs, Support Numbers, Account Managers Info etc so that you don’t have to search it everytime.

What You Need:

8. Visio: When it comes to tools, Microsoft Visio is the best one I have seen. You would need stencils to give a real picture of your datacenter. Generic ones should be avoided or should be used only for logical explanations like routing/firewall setups, but what if you need to show actual physical connections? I have seen many usual stencils available on Visio-cafe (ask Google); rest you can ask the vendor for it, they usually provide it as free of cost. Note that there are certain open-source tools available, but they may or may not give the precision to show-case your datacenter. I may be biased, but I am just a fan of Visio.

9. Information: Apart from tools information is most important. It may be available like a document for setups or like an excel sheet for inventory. Make sure you validate the inventory before you actually deploy it. Most important, you need to make sure this information is kept up to date.

10. Owner, Reviewers & Approvers: To make sure you have the proper information and its mapped as is; Get it reviewed from your peers (Important). See if they have any comment or suggestion or doubts before you actually publish it. What’s the use of it, if they don’t understand it. Like I mentioned before, its less technical document but more logical document. Owners are required to keep information up to date and approvers are required so that this can be use a standard reference documents and can be published.

Special Notes:

There are couple of tools available which easy your work for making automatic diagram via environment discovery like HP SAN Visibility (free), VMware Maps (free) and some other third party tools. However, you would need to consider the pros and cons that comes with these tools like support limitation, cost, credentials or access requirements etc. Adding to it no tool shows you rack placement.

Any more questions? please write back or comment here. There are more things to share..

Happy Learning!!

P.S.: I understand the example was given using small deployments, but it may look tedious when it comes to bigger deployments. Yes! It will be, if done by one man army J suggested to divide the work with respective areas of expertise or domain to make it easy, which can be later complied together.

Tuesday, 9 December 2014

Free Backup Professional Certification: I am sure another 'TING' happened :)

My previous post about Free Cloud certification was a big hit and got viewers from all over the world. I realized that people are interested in free learning and certification as well, since they are the parameters on which industries tends to measure our skills (though personally I don't feel that's really important, Knowledge is all that matters). Anyways..

Well, Yes!! Its Another Free Certification!! For those of you who don't know this, A free Certification is offered by VEEAM, who is a leading brand for Virtual Machine backups. All it requires is for you to go through free videos by some experts like David Davis, Elias Khnaser, Eric Siebert, David Hill etc available on this Link

This is a good source for learning about backup technology too. However, if you think you already have knowledge about backups, you can directly appear for the Exam. So as you can see its not mandate to watch all videos or complete all video sessions, though its a good refresher to revise your basics. It has some 33 questions and you need to pass with 75%, which I felt was easy to crack. You can even test your existing knowledge with Quick Test

Just follow the link:
http://www.backupacademy.com/

Any more questions? please write back or comment here. There are more things to share..

Request you to join my group on Facebook & LinkedIN with name "DataCenterPro" to get regular updates. I am also available on Tweeter as @_anubhavjain. Shortly I am going to launch my own YouTube channel for free training videos on different technologies as well.

Happy Learning!!

Sunday, 7 December 2014

DataCenter 101 - Labeling Your DataCenter

Labeling of the data center is as important as Cabling in DataCenter, since deploying a DataCenter may be easy, however troubleshooting it can be a mess when you need to track the cables. A Label gives the information about the equipment. So lets discuss some points to remember about Labeling:

· A Label should always have a clear font with bright background to make it readable.

· Always make 2 labels for the equipment, so that it can be pasted on both rear & front side of the equipment, where one on of them should be pasted near its management port.

· During cable connectivity between equipment, label the cable immediately on both ends, to avoid future hassle. Doing Labeling after deployment can be tedious and may require double effort in bigger infrastructure.

· Labeling a cable (Power, LAN, FC, FCoE, FC ISL, LAN Uplinks) can be done before deploying the cable as well if location of the other equipment is too far. You can mention the equipment’s location along with other details over the label.

· Hostname of the equipment (fixed) like of Switches, can be made in a format where we can track its location as well. This can help tracking switch in datacenter, rather maintaining a separate inventory for switch location.

Special Format Tips

For Blade enclosure, mention its Hostname and Management IP in its label. Create two labels, so that it can be posted in both rear & front side of blade enclosure, which can help anyone to track the equipment.

· Labels of cables going from a switch should point to the other end of the cable. In this scenario, always put two labels on each side of cable, one label should mention the device its connected to (switch name, IP), other should mention the location/port number# in the switch. The more details you will provide, the more easy it will be for anyone to walk-in datacenter & perform troubleshooting in case of any issues.

· Label for a power socket should point to its respective transformer/phase say TXXPXX

· Label for Storage should have its name, management IP and its WWN. All ports in storage should be labeled properly pointing to its target switch IP/Port as well. Cable labels can be in format of say SN-IP-PRT e.g. S30P24ISL, where it points to Switch30 Port 24, and it also says it’s a “ISL” port for FC. In case of Storage roles of a port can be “Mgmt”, “Host port”, “Disk Port” or “Remote Copy” and even “Misc” based on services available in array.

A question might arise in mind that why do I need label since every equipment has its own serial number pasted over it. Well, as per my experience, it would be really difficult when you have to track server by its serial number specially in a time of crisis or server failure, which need to be troubleshoot locally or physically. You can keep a record where it shows you the location of server as its Floor#-Row#-Rack# e.g. 02F2407, however a rack may have many other equipment of equipment with same kind of configuration, look and feel. To keep things easy, its always good to have a label, so that whenever you have any issue, you can look into your database or records (can be an excel sheet), go to the location of the rack and looking at the label without wasting time searching a serial number, you can start your work.

Special Label

· You can post “warnings” on server playing vital roles in datacenter or which are very critical as per its role internally or for the customer. You can also mention its “role” is required. These kind of labels are very handy especially when you are working in a R&D environment or Labs, where a user might be required to walk-in lab or perform some tasks as per project requirements.

· You might be required to paste the “asset tag” bar code on the equipment as well.

· You can even post a printout of the visio/logical architecture of connectivity in between equipment or keep it handy so that it would be easy to track the point of failure and resolve the issue ASAP.

· In case of small project, a project can keep a visio diagram which shows the exact connectivity in data center for their equipment, which will have its port, IP, uplink, location etc mentioned in the diagram itself along with OS and other minute information like firmware versions as well. This can be helpful for R&D Labs or environments.

Pasting the Labels

· Labels should be pasted on equipment where its visible and clear

· While pasting the label on an equipment, one of the two label should be pasted near its management port.

· Paste label on both rear & front side of the equipment.

· For cables, pasting a label is tricky and should be done with Caution. If it’s a LAN Cable, Patch Cord or Power cable, it can be pasted completely along its length.

Special Note:

· You can use special equipment like label printing machines or also called as Label Printer, which gives you neat, laminated, formatted labels. Sizes available for labels can be 12MM & 24MM, however Color of the label may vary from vendor to vendor. You may Google it to see how it looks in case you haven’t seen one.

· Usually most preferred colors are “White” & “Yellow” base with Black Ink.

· 12MM is used for cables, Switches, Rack mount server of space using up to 1U/2U, while 24MM will be used for equipment like Blade enclosure, Storage arrays etc, wherever we have equipment which consume space more than or equal to 4-8U.

· You can also use Cable Numeric Markers for Patch Cord cables (see picture attached)

· Keep the overview of data center handy. You can create Visio diagrams of each rack with its location and show exact or logical connectivity of equipment inside it. You can even mention about ISL/Uplinks going from or to the rack.

DataCenter 101 – DataCenter Cabling Strategies

In my last article about Rack Fundamentals, we discussed about how the racks to be chosen for deployment. Once are racks are deployed, and equipment are stacked over it, we need to interconnect them via Cables. Cabling is the key activity when it comes to building of a Datacenter. It does take huge amount of efforts and need specialists to do this activity. It may sound cabling is just plug-in of cable from source to target ports, but is that it?

Designing your DataCenter and implementing its core components is most crucial part to handle when it comes to Managing your DataCenter. This includes all the data cables i.e. your LAN Network Cables (Copper, Fiber) or SAN cables (Copper, Fiber) and Power Distribution Cables.

I don’t think we need to go back to the history about when the cabling of DataCenter was taken into considerations. However, they do play a vital role to understand your Network Topology. Still, I would be giving you an overview just to refresh about the kind of cables we usually use in DataCenter.

Overview of Cable & Connectors:

· Network: CAT5 of Category 5 is used for 100MB connection, while Cat 5e support 1G and Cat6a supports 10G connection. For Network LAN Copper Cables RJ45 is the common connector type, which is supported for Data Speed max up to 1GBPS. You might have seen this with your Broadband connection or office Ethernet connection. For 10G LAN Network, Fiber channel cables are mostly used for connectivity. However, there are 10G Copper cables available, mostly seen used with blade enclosure modular switches. SFP+ are factory installed with 10G copper cables. Even for storage array connectivity within system i.e. from controller to JBOD, mostly 10G Copper SAS cables are used.

· Storage: FC cables are used mostly with Storage SAN connections. The most commonly used are 2G/4G/8G/16G connections. For 1G/2G Yellow color, 2G/4G Orange color, 8G/10G Aqua colors while for 16G Dark Blue color cables are used. FC cables are further connected to respective speed SFP+, note that these SFP+ are backward speed compatible. However If a high speed cable is connected to lower speed SFP+ it will work in respective speed. I have also seen people using certain SFP+ which are used to connect RJ45 cable with 10G ports.

· Power: For Power Distributions, usually 6A/12A cables are used with server, storage & Switches. 12A cable is mostly used with Blade enclosures, High End Servers or with an Enterprise Storage device. Just to recognize, 6A cables are with oval curve and usually seen along with Desktop computers as well, while 12A are rectangular in shape and is uniquely identified.

· Misc Cables: These are equipment specific or management cables like Serial cables, KVM or ILO cables etc

Now I am not getting into the specifications of each cables or the cables to be considered like LC/SC, OM1/2/3/4 etc, that would be a separate chapter all together, which I would cover when I will start discussing about Storage in future blogs. However if you are curious Wiki can help you. I am also not covering how to make these cables or how to connect these cables. For this, I would be making a video shortly in my Video learning series.

For Power Distribution:

· Power from Large UPS or Transformers is taken and stepped down to receive correct voltage and distributed along panel mounted in the columns

· Power is then further distributed from columns to rack mounted power distribution units via Whip (to avoid raised floor expenses).

· Each equipment will be then further wired to these PDU for connection based on their requirements.

· Remember Amp X Voltage = Power; so as the Amp increases or decreased, the gauge of the wire needs to be increase or decrease to accommodate the change.

· Considering the High Availability, always plug-in both the PDU of equipment to different phases or power feeds

Note: Load per rack or circuit load need to considered while wiring these hardware

Cabling Layout Architecture:

· Remember the old school network topology you studied while learning about Networks and we learned how network can be designed with Star, Bus, Ring and Tree topology. Well, for data centers, a Star topology is used.

· Many factors need to be considered while deciding a layout for power distributions e.g. size of the datacenter, kind of equipment, budgets etc

· Usually power distribution panels are installed at the end of the row from where is further distributed across racks in that row. This approach is easy to manage and less expensive as well. Also, it breaks whole circuit into multiple points which avoids a bigger failure in case of any incident.

Data Cabling Practices:

· Follow National Electric Code as Standard for deployment

· Test cable before deployment.

· Prefer Over-head Deployments with cabling trays; not suggest if constant change is expected since not scalable. Note they should have sufficient distance away from sprinklers.

· Don’t tie the cables with Rack

· Don’t over tight the length of the cable, use the right length required. Don’t keep them lose either. Use cable guidance closets for the deployment. Cable guiding trays and their management devices reduces downtime by avoiding human error and over-heating.

· Cables connected via Patch Panels installed over (every) rack. These patch panels are designed and deployed in initial phase of DataCenter deployment.

· Cable back-bone in a rack should be preferred non-scalable. However, it is a best practice to wire as much as possible with latest cable standard during initial deployment.

· Cables should be located behind the walls and should not be in open

· Most important, once the cables are deployed, Label them. I would be writing a my next article regarding best practices for cabling.

Caution: Do consider the scenarios while designing when your patch cable will fail.

Tuesday, 2 December 2014

Meet Your DataCenter - An Overview

There has been a buzz about Cloud computing, Virtualizations, etc, but whats behind all this? Its your DataCenter. The very first thing you need to keep in mind is your DataCenter should be Scalable, flexible, adaptable and most important cost-effective. You need to plan even the unseen demands on resources like electrical power and cooling, as it can increase costs and lead to performance issues if not fulfilled or even outages.

The physical layer of datacenter is the base upon which all network, storage, servers resources sits, further which gives platforms to business critical applications or even platforms like virtualization or cloud computing.

DCPI or DataCenter Physical Infrastructure is a one layer below the computing later i.e. our servers, storage and network. It involves the following components:

· Power: It consists of multiple components which make the power distribution possible across datacenter. These components are - The Generators, Batteries, UPS, Serge Protectors, Transformers, Distribution Panels and Circuit Breakers. This is the only components which hasn’t changed much over decades, now I am not referring to the ways we generate them or monitor them but the components itself haven’t changed much. When originally the power distribution components were designed, their principles were not actually meant for IT infrastructures, which lead to the challenges as mentioned below. It is clear that why integration of components of the power system started to move towards pre-engineered and manufactured solutions like Modular and Scalable components.

· Cooling: It involves the system which removes or overcomes the heat from the datacenter. This involves chillers, cooling towers, condensers, duct work, pumps, piping and rack level distributions. Just like Power, evening cooling system haven’t emerged or changed much over these years which lead to the same challenges as faced in Power. There has been a change in how cooling was done in past few years, though this technologies have not been much adapted yet in market.

· Racks: Racks are the cabinet which holds the equipment. These racks should be considered and designed during design phase of datacenter. The old standards for Racks were IEC 297-3 for mechanical dimensions while EIA 310 for rack mounting of Telecomm and IT equipment. These days mostly TIA941 has been considered as Standard. Mostly 42U racks are considered as standard and all equipment including server, storage or network are designed to kept in standard racks. A detailed article is already published on this blog as “Rack Fundamentals"

· Physical Security/Fire Protections: This includes physical security devices at rack and datacenter level e.g. keys (commonly used), biometric, codes or access cards while Fire protection system includes smoke detectors, clean agents or heat detection sensors. These days they are mandate when it comes to standardizing the datacenter. NFPA (National Fire Protection Association) established in 1896, imposes standards, codes, research, training and education worldwide to reduce fire and other hazards scientifically. NFPA-75 is the standard for the protection of electronic computer or data processing equipment.

· Cabling: This is most when it comes to designing and managing datacenter, this includes all data cables and power cables within datacenter. Some best practices for cabling are:

o Overhead deployments to make sure there is

o Underfoot deployments

o Rack installation with guidance cables

o Do not tie or hang cables

o Testing of cables before installation

o Most important, Label these cables to trace back.

o Power cabling best practice are available I National Electric Code, under continuous load cables

o Cables should not be undersized or stretched

o Use cable raise rather preferring raised floors

A detailed article is already published on this blog as “Cabling Strategies”

· Management: Managing the datacenter includes Building Management System (BMS), Network Management System (NMS), and Enterprise Management System (EMS), Element Managers and other software and hardware. A detailed article is already published on this blog as “Managing your Datacenter” in three parts

· Services: To perform several operations in DataCenter, many services are required to support DCPI which includes – Consulting and design, Installation, Maintenance, Monitoring and Decommission services.

Integration of these aspects are taken care in the Design phase of the DataCenter. Usually, its all about a Plan, which would be Constructed and then Deployed. Be it any component in your computing layer, storage, server or network, they cannot work efficiently till your DCPI works fine. Adding above, there are three more important components which together with DCPI make things work for you. It’s the:

· People: Well most Important you need to people which appropriate skills and levels of expertise to run the datacenter

· Process: It includes the Standard Operation Procedures, which should be well documented as well. A detailed article is already published on this blog as “Documenting your Datacenter”

· Information Technology: which includes hardware and software used for data processing, storage and communication

Note that more detailed articles will be published on above topics, this was just an overview. In my next article, we will start looking at individual components of DataCenter.