Related Topics: SDN Journal, Containers Expo Blog

SDN Journal: Blog Feed Post

Data Center Architecture: Together and Apart

The datacenter represents a diverse set of orchestrated resources bound together by the applications they serve

The challenge in architecting, building, and managing data centers is one of balance. There are forces competing to both push together and pull apart datacenter resources. Finding an equilibrium point that is technological sustainable, operationally viable, and business friendly is challenging. The result is frequently a set of compromises that outweigh the advantages.

Logically together

The datacenter represents a diverse set of orchestrated resources bound together by the applications they serve. At its most simplest, these resources are physically co-located. At its extreme, these resources are geographically distributed across many sites. Whatever the physical layout, these resources are under pressure to be treated as a single logical group.

Resource collaboration - The datacenter is a collection of compute and storage resources that must work in concert in support of application workloads. The simple requirement of coordination creates an inward force pulling resources closer together, even if only logically. How can multiple elements work together towards a common goal if they are completely separate?

The answer is that they cannot. And as IT moves increasingly towards distributed applications, the interdependence between resources only grows.

Interestingly, the performance advantages of distributed architectures are only meaningful when communication between servers is uninhibited. If the network that makes communication possible slows down, the efficacy of the distributed architecture decreases. This means that datacenter architects must solve simultaneously for compute and storage demand, and the interconnect capacity required between them.

Resource availability - Building out a datacenter is an exercise in matching resource capacity to demand. But not just in aggregate.

Individual applications, tenants, and geographies all place localized demands on datacenter resources. If the aggregate demand is sufficient but the resources exist in separate resource pools, you end up in a perpetual state of mismatch. There is always too much or too little workload capacity. The former means you have overbuilt. The latter leaves you wanting for more, which oddly enough means you end up having to overbuild.

Combatting these resource islands requires pulling resources closer together. In the most simple case, this is a physical act. But even if resources cannot be physically co-located, there are entire classes of technologies whose primary function is to allow physically separate resources to behave as if they are in close proximity.

Of course this does not come without a cost. The complexity of managing the disparate technologies required to logically pool physically separate resources can be prohibitively difficult. Even the most skilled specialists have to invest time in creating a properly engineered fabric between sites that accounts for queuing, prioritization, load balancing, and so on. The number of protocols and technologies required is high, and the volume of devices over which they must be applied can be huge. The result is a level of complexity that makes the network more expensive to manage and more difficult to change.

Organizational process - Friction is greatest at boundaries. Whenever a task requires involvement across different organizations or teams, the act of human coordination imposes a tax on both effort and time. In larger organizations, the handoff between teams might be automated to reduce communication mistakes (as with a ticketing system), but the shift in context is still expensive.

This creates organizational pressure to pull together things that might otherwise be separate. If distributed resources can be logically centralized and managed within a common organization, it reduces the dependence on outside teams. The removal of boundaries from common workflows lowers organizational friction and makes easier the overall task of managing the infrastructure.

Physically separate

At the same time that forces are pulling things together, there are equally strong oppositional forces exerting outward pressure on datacenter resources.

Business continuity - For many companies, the datacenter represents a mission critical element of their infrastructure. For companies whose existence depends on the presence of the resources within the datacenter (be they data, servers, or applications), it is untenably risky to rely on a single physical site. This exerts an outward force on resources as companies must create multiple physical sites, typically separated by enough distance that a disaster would not meaningfully impact all sites.

Despite the operational desire to keep things together, the risk to the business dictates that resources be physically separate.

Natural expansion - As resources are added to a datacenter, they are typically installed in racks in relative close proximity to each other. When racks are empty, there is no reason to unnecessarily create physical separation between resources working in concert. Over time, adjacent rack space is filled through the natural expansion of compute, storage, and networking capacity.

As equipment expands, available rack space is depleted, and new racks and rows are populated. Eventually, the device sprawl can occupy entire data centers.

Imagine now that a cluster of servers occupies a rack in one corner of the datacenter. If that cluster is to be expanded, where does the next server go? If the nearby racks are already built out, that resource must be installed some physical distance away from the resources with which it must coordinate.

It is near impossible to plan for all future growth at the time of datacenter inception. Leaving enough space in adjacent racks to account for a decade of growth is impractically expensive. A sparsely populated datacenter suffers from poor space utilization, challenging power distribution, and difficult cabling. Thus, the mere act of expansion actually exerts an outward force leading to physically distributed resources.

Real estate - Sometimes, even when architects want to keep resources together, physical limitations create problems. There is no more immovable object than real estate (which serves as a proxy for all of space, power, and HVAC). In some cases, it is impossible to build out either laterally or even up. In other cases, there is no additional power to be had from the grid. Either of these scenarios forces an expansion to another site, which requires the physical separation of resources that might be expected to function in concert.

Additionally, as land rates change and technologies evolve, the best spots for data centers are not always known. It is difficult at best to predict with enough certainty how a physical site will evolve over an arbitrarily long time horizon. For example, not long ago, the thought of building cooling-hungry data centers in the hot desert was foreign. Today, Las Vegas is home to some of the most cutting edge facilities in the world. This means that geographical dispersion is likely a certainty for large companies. The forces pulling resources physically apart are unlikely to be neutralized.

Finding a balance

Given the strong forces working to keep resources logically together and the equally strong forces keeping them physically separate, how does anyone find a balance?

The price for balance is cost and complexity. You pay for reach directly, and control requires complexity. Both translate into higher carrying costs for the infrastructure. The push-pull dynamic in datacenters is not going away anytime soon. In fact, a move towards more distributed applications will only make harder the balancing act that already exists.

Newer technology offerings like SDN and datacenter fabrics offer some hope, but only insofar as they offer alternatives to the existing problems. Whatever the solution, architects will need to evaluate approaches based not just on the features but on the long-term costs of those features.

[Today’s fun fact: “Way” is the most frequently used noun in the English language. No way!]

The post Datacenter architecture: Together and apart appeared first on Plexxi.

More Stories By Michael Bushong

The best marketing efforts leverage deep technology understanding with a highly-approachable means of communicating. Plexxi's Vice President of Marketing Michael Bushong has acquired these skills having spent 12 years at Juniper Networks where he led product management, product strategy and product marketing organizations for Juniper's flagship operating system, Junos. Michael spent the last several years at Juniper leading their SDN efforts across both service provider and enterprise markets. Prior to Juniper, Michael spent time at database supplier Sybase, and ASIC design tool companies Synopsis and Magma Design Automation. Michael's undergraduate work at the University of California Berkeley in advanced fluid mechanics and heat transfer lend new meaning to the marketing phrase "This isn't rocket science."

Latest Stories
Both SaaS vendors and SaaS buyers are going “all-in” to hyperscale IaaS platforms such as AWS, which is disrupting the SaaS value proposition. Why should the enterprise SaaS consumer pay for the SaaS service if their data is resident in adjacent AWS S3 buckets? If both SaaS sellers and buyers are using the same cloud tools, automation and pay-per-transaction model offered by IaaS platforms, then why not host the “shrink-wrapped” software in the customers’ cloud? Further, serverless computing, cl...
You know you need the cloud, but you’re hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You’re looking at private cloud solutions based on hyperconverged infrastructure, but you’re concerned with the limits inherent in those technologies.
With the introduction of IoT and Smart Living in every aspect of our lives, one question has become relevant: What are the security implications? To answer this, first we have to look and explore the security models of the technologies that IoT is founded upon. In his session at @ThingsExpo, Nevi Kaja, a Research Engineer at Ford Motor Company, discussed some of the security challenges of the IoT infrastructure and related how these aspects impact Smart Living. The material was delivered interac...
The taxi industry never saw Uber coming. Startups are a threat to incumbents like never before, and a major enabler for startups is that they are instantly “cloud ready.” If innovation moves at the pace of IT, then your company is in trouble. Why? Because your data center will not keep up with frenetic pace AWS, Microsoft and Google are rolling out new capabilities. In his session at 20th Cloud Expo, Don Browning, VP of Cloud Architecture at Turner, posited that disruption is inevitable for comp...
Wooed by the promise of faster innovation, lower TCO, and greater agility, businesses of every shape and size have embraced the cloud at every layer of the IT stack – from apps to file sharing to infrastructure. The typical organization currently uses more than a dozen sanctioned cloud apps and will shift more than half of all workloads to the cloud by 2018. Such cloud investments have delivered measurable benefits. But they’ve also resulted in some unintended side-effects: complexity and risk. ...
It is ironic, but perhaps not unexpected, that many organizations who want the benefits of using an Agile approach to deliver software use a waterfall approach to adopting Agile practices: they form plans, they set milestones, and they measure progress by how many teams they have engaged. Old habits die hard, but like most waterfall software projects, most waterfall-style Agile adoption efforts fail to produce the results desired. The problem is that to get the results they want, they have to ch...
IoT solutions exploit operational data generated by Internet-connected smart “things” for the purpose of gaining operational insight and producing “better outcomes” (for example, create new business models, eliminate unscheduled maintenance, etc.). The explosive proliferation of IoT solutions will result in an exponential growth in the volume of IoT data, precipitating significant Information Governance issues: who owns the IoT data, what are the rights/duties of IoT solutions adopters towards t...
"We are a monitoring company. We work with Salesforce, BBC, and quite a few other big logos. We basically provide monitoring for them, structure for their cloud services and we fit into the DevOps world" explained David Gildeh, Co-founder and CEO of Outlyer, in this SYS-CON.tv interview at DevOps Summit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
In 2014, Amazon announced a new form of compute called Lambda. We didn't know it at the time, but this represented a fundamental shift in what we expect from cloud computing. Now, all of the major cloud computing vendors want to take part in this disruptive technology. In his session at 20th Cloud Expo, Doug Vanderweide, an instructor at Linux Academy, discussed why major players like AWS, Microsoft Azure, IBM Bluemix, and Google Cloud Platform are all trying to sidestep VMs and containers wit...
"When we talk about cloud without compromise what we're talking about is that when people think about 'I need the flexibility of the cloud' - it's the ability to create applications and run them in a cloud environment that's far more flexible,” explained Matthew Finnie, CTO of Interoute, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
While DevOps most critically and famously fosters collaboration, communication, and integration through cultural change, culture is more of an output than an input. In order to actively drive cultural evolution, organizations must make substantial organizational and process changes, and adopt new technologies, to encourage a DevOps culture. Moderated by Andi Mann, panelists discussed how to balance these three pillars of DevOps, where to focus attention (and resources), where organizations might...
The Internet giants are fully embracing AI. All the services they offer to their customers are aimed at drawing a map of the world with the data they get. The AIs from these companies are used to build disruptive approaches that cannot be used by established enterprises, which are threatened by these disruptions. However, most leaders underestimate the effect this will have on their businesses. In his session at 21st Cloud Expo, Rene Buest, Director Market Research & Technology Evangelism at Ara...
No hype cycles or predictions of zillions of things here. IoT is big. You get it. You know your business and have great ideas for a business transformation strategy. What comes next? Time to make it happen. In his session at @ThingsExpo, Jay Mason, Associate Partner at M&S Consulting, presented a step-by-step plan to develop your technology implementation strategy. He discussed the evaluation of communication standards and IoT messaging protocols, data analytics considerations, edge-to-cloud tec...
New competitors, disruptive technologies, and growing expectations are pushing every business to both adopt and deliver new digital services. This ‘Digital Transformation’ demands rapid delivery and continuous iteration of new competitive services via multiple channels, which in turn demands new service delivery techniques – including DevOps. In this power panel at @DevOpsSummit 20th Cloud Expo, moderated by DevOps Conference Co-Chair Andi Mann, panelists examined how DevOps helps to meet the de...
When growing capacity and power in the data center, the architectural trade-offs between server scale-up vs. scale-out continue to be debated. Both approaches are valid: scale-out adds multiple, smaller servers running in a distributed computing model, while scale-up adds fewer, more powerful servers that are capable of running larger workloads. It’s worth noting that there are additional, unique advantages that scale-up architectures offer. One big advantage is large memory and compute capacity...