Welcome!

@CloudExpo Authors: Liz McMillan, Elizabeth White, Pat Romanski, Jeev Trika, Sujoy Sen

Related Topics: @CloudExpo

@CloudExpo: Blog Feed Post

Evaluating Cloud Computing Uptime SLAs

How many of us evaluate the vendor's Service Level Agreement (SLA) before they decide to deploy workloads in the cloud?

Last week's Windows Azure Storage outage made me thinking how many of us evaluate the vendor's Service Level Agreement (SLA) before they decide to deploy workloads in the cloud. I bet many think about it only when it is too late.



Let's take Windows Azure SLA and see how we as consumers of the cloud services are protected in case of downtime. Before all though I would like to point out that it is in the nature of any service (public or private) to experience outage once in a while - think about power outages that we hear about or live through every winter. It is important to understand that this will happen and as users of cloud services we need to be prepared for it. In this post I will use Windows Azure as example not because their services are better or worse than the other cloud vendors but to illustrate how the SLAs impact us and how they differ from vendor to vendor.

Each SLA (or at least the ones that bigger cloud vendors offer) contains few main sections:

  • Definitions - defining the terms used in the document
  • Claims - describing how and under what terms one can submit a claim for incidents as well as how much you will be credited
  • Exclusions - describing in what cases the vendor is not liable for the outage
  • The actual SLAs - those can be two types:
    • Guaranteed performance characteristics of the service
    • Uptime for the service

Looking at Windows Azure SLAs web page the first thing you will notice is that there are different SLAs for each service. You don't need to read all of them unless you utilize all of the services the vendor offer. The main point here is that you need to read the SLAs for the services you use. If, for example you use Windows Azure Storage and Windows Azure Compute you will notice that the uptime for those differ by 0.05% (Compute has uptime guarantee of 99.95% while Storage has uptime guarantee of 99.90%). Although this number is negligible at first sight using an SLA calculator you will notice that the expected downtime for Storage is twice as much as the expected downtime for Compute. It is obvious that the closer the uptime is to 100% the better the service is.

The next thing that you need to keep in mind is the timeframe for which the uptime is calculated for. In the case of Windows Azure the uptime is guaranteed on a monthly basis (for both Storage and Compute). In comparison Amazon's EC2 has annual uptime guarantee. Monthly SLA guarantees are preferable because you will avoid the case where the service experiences severe outage in particular month and stays up the rest of the year. Just to illustrate the last point imagine that EC2 experiences outage of 3h in particular month and stays up for the next 11 months. This outage is less than the 99.95% guarantee or 4:22:47.99 hours acceptable downtime per year and you will not be eligible for credit for it. On the other side if the SLA guarantee is on a monthly basis you will be eligible for the maximum credit for it because it severely exceeds the 21 minutes acceptable downtime per month.

One note about the acceptable downtime. In reality hardware in cloud data-centers fails all the time, which may result in downtime for your particular service but will not impact other services or workloads. Such outages are normally covered by the exclusion clause of the SLA and are your own responsibility. You should follow the standard architectural practices for cloud application and always make your services redundant in order to avoid this. The acceptable downtime metric is calculated for outages that impact vast amount of services or customers. Surprisingly though nowhere in the SLAs is mentioned how many customers need to be impacted in order for the vendor to report the outage. It may happen that a rack of servers in the datacenter goes down and few tens of customers are impacted for some amount of time. If you are one of those do not expect to see official statement from the cloud vendor about the outage. As a rule of thumb if the outage doesn't show up in the news you may have hard time proving that you deserve credit.

The last thing to keep in mind when evaluating SLAs from big cloud providers is the Beta and trial services. It is simple - there are no SLAs for services released in Beta functionality. You are free to use them at your own risk but don't expect any guarantees for uptime from the vendor.

When the so called secondary cloud providers are concerned you need to be much more careful. Those providers (and there are a lot of them) build their services on top of the bigger cloud vendors and thus are very dependent on the uptimes from the big guys. Hence they don't publish standard SLAs but negotiate the contracts on customer-by-customer basis. Most of the time this is based on the size of business you create for them and you can rely on good terms if you are big customer. Of course they put a lot of effort in helping you design your application for redundancy and avoid the risk of executing the SLA because of primary vendor outage. In the opposite case where you are a single developer you may end up without any guarantees for uptime from smaller cloud vendors.

More Stories By Toddy Mladenov

Toddy Mladenov has more than 15 years experience in software development and technology consulting at companies like Microsoft, SAP and 3Com. Currently he is a CTO of Agitare Technologies, Inc. - a boutique consulting company that specializes in Cloud Computing and Big Data Solutions. Before Agitare Tech Toddy spent few years with PaaS startup Apprenda and more than six years working on Microsft's cloud computing platform Windows Azure, Windows Client and MSN/Windows Live. During his career at Microsoft he managed different aspects of the software development process for Windows Azure and Windows Services. He also evangelized Microsoft cloud services among open source communities like PHP and Java. In the past he developed enterprise software for German's software giant SAP and several startups in Europe, and managed the technical sales for 3Com in the Balkan region.

With his broad industry experience, international background and end-user point of view Toddy has an unique approach towards technology. He believes that technology should be develop to improve people's lives and is eager to share his knowledge in topics like cloud computing, mobile and web development.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@CloudExpo Stories
In his session at 18th Cloud Expo, Bruce Swann, Senior Product Marketing Manager at Adobe, will discuss how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects). Bruce Swann has more than 15 years of experience working with digital marketing disciplines like web analytics, social med...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, will provide an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life ...
What a difference a year makes. Organizations aren’t just talking about IoT possibilities, it is now baked into their core business strategy. With IoT, billions of devices generating data from different companies on different networks around the globe need to interact. From efficiency to better customer insights to completely new business models, IoT will turn traditional business models upside down. In the new customer-centric age, the key to success is delivering critical services and apps wit...
The essence of data analysis involves setting up data pipelines that consist of several operations that are chained together – starting from data collection, data quality checks, data integration, data analysis and data visualization (including the setting up of interaction paths in that visualization). In our opinion, the challenges stem from the technology diversity at each stage of the data pipeline as well as the lack of process around the analysis.
Enterprise networks are complex. Moreover, they were designed and deployed to meet a specific set of business requirements at a specific point in time. But, the adoption of cloud services, new business applications and intensifying security policies, among other factors, require IT organizations to continuously deploy configuration changes. Therefore, enterprises are looking for better ways to automate the management of their networks while still leveraging existing capabilities, optimizing perf...
Many banks and financial institutions are experimenting with containers in development environments, but when will they move into production? Containers are seen as the key to achieving the ultimate in information technology flexibility and agility. Containers work on both public and private clouds, and make it easy to build and deploy applications. The challenge for regulated industries is the cost and complexity of container security compliance. VM security compliance is already challenging, ...
@DevOpsSummit taking place June 7-9, 2016 at Javits Center, New York City, and Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 18th International @CloudExpo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, will explore the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences betwee...
SYS-CON Events announced today that ContentMX, the marketing technology and services company with a singular mission to increase engagement and drive more conversations for enterprise, channel and SMB technology marketers, has been named “Sponsor & Exhibitor Lounge Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York City, New York. “CloudExpo is a great opportunity to start a conversation with new prospects, but what happens after the...
SYS-CON Events announced today that 24Notion has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. 24Notion is full-service global creative digital marketing, technology and lifestyle agency that combines strategic ideas with customized tactical execution. With a broad understand of the art of traditional marketing, new media, communications and social influence, 24Notion uniquely understands how to con...
In his session at 18th Cloud Expo, Andrew Cole, Director of Solutions Engineering at Peak 10, will discuss how the newest technology advances are reducing the cost and complexity of traditional business continuity and disaster recovery solutions. Attendees will: Learn why having a full disaster recovery strategy is more important now than ever before Explore the key drivers of a successful disaster recovery solution Achieve measurable operational and business value from a disaster recovery ...
SYS-CON Events announced today the Docker Meets Kubernetes – Intro into the Kubernetes World, being held June 9, 2016, in conjunction with 18th Cloud Expo | @ThingsExpo, at the Javits Center in New York, NY. Register for 'Docker Meets Kubernetes Workshop' Here! This workshop led by Sebastian Scheele, co-founder of Loodse, introduces participants to Kubernetes (container orchestration). Through a combination of instructor-led presentations, demonstrations, and hands-on labs, participants learn ...
The initial debate is over: Any enterprise with a serious commitment to IT is migrating to the cloud. But things are not so simple. There is a complex mix of on-premises, colocated, and public-cloud deployments. In this power panel at 18th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists will look at the present state of cloud from the C-level view, and how great companies and rock star executives can use cloud computing to meet their most ambitious and disruptive business ...
The demand for organizations to expand their infrastructure to multiple IT environments like the cloud, on-premise, mobile, bring your own device (BYOD) and the Internet of Things (IoT) continues to grow. As this hybrid infrastructure increases, the challenge to monitor the security of these systems increases in volume and complexity. In his session at 18th Cloud Expo, Stephen Coty, Chief Security Evangelist at Alert Logic, will show how properly configured and managed security architecture can...
SYS-CON Events announced today that Hanu Software will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Leveraging best-in-class people, processes, and technologies, Hanu provides high-quality, high-value software development and business process outsourcing services to independent software vendors (ISVs) and enterprises.
When it comes to IoT in the enterprise, namely the commercial building and hospitality markets, a benefit not getting the attention it deserves is energy efficiency, and IoT's direct impact on a cleaner, greener environment when installed in smart buildings. Until now clean technology was offered piecemeal and led with point solutions that require significant systems integration to orchestrate and deploy. There didn't exist a 'top down' approach that can manage and monitor the way a Smart Buildi...
SYS-CON Events announced today BZ Media LLC has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. BZ Media LLC is a high-tech media company that produces technical conferences and expositions, and publishes a magazine, newsletters and websites in the software development, SharePoint, mobile development and Commercial Drone markets.
SYS-CON Events announced today TechTarget has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. TechTarget is the Web’s leading destination for serious technology buyers researching and making enterprise technology decisions. Its extensive global networ...
As machines are increasingly connected to the internet, it’s becoming easier to discover the numerous ways Industrial IoT (IIoT) is helping to shape the business world. This is exactly why we have decided to take a closer look at this pervasive movement and to examine the desire to connect more things! Now if you need a refresher on IIoT and how it is changing the world, take a moment and listen to Greg Gorbach with ARC Advisory Group. Gorbach believes, "IIoT will significantly change the worl...
The pace of innovation, vendor lock-in, production sustainability, cost-effectiveness, and managing risk… In his session at 18th Cloud Expo, Dan Choquette, Founder of RackN, will discuss how CIOs are challenged finding the balance of finding the right tools, technology and operational model that serves the business the best. He will discuss how clouds, open source software and infrastructure solutions have benefits but also drawbacks and how workload and operational portability between vendors...