Click here to close now.

Welcome!

Cloud Expo Authors: Carmen Gonzalez, Elizabeth White, Pat Romanski, Adrian Bridgwater, William Schmarzo

Related Topics: Cloud Expo

Cloud Expo: 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
Over the years, a variety of methodologies have emerged in order to overcome the challenges related to project constraints. The successful use of each methodology seems highly context-dependent. However, communication seems to be the common denominator of the many challenges that project management methodologies intend to resolve. In this respect, Information and Communication Technologies (ICTs) can be viewed as powerful tools for managing projects. Few research papers have focused on the way...
As the world moves from DevOps to NoOps, application deployment to the cloud ought to become a lot simpler. However, applications have been architected with a much tighter coupling than it needs to be which makes deployment in different environments and migration between them harder. The microservices architecture, which is the basis of many new age distributed systems such as OpenStack, Netflix and so on is at the heart of CloudFoundry – a complete developer-oriented Platform as a Service (PaaS...
As cloud gives an opportunity to businesses to buy services externally – how is cloud impacting your customers? In his General Session at 15th Cloud Expo, Fabio Gori, Director of Worldwide Cloud Marketing at Cisco, provided answers to big questions: Do you see hybrid cloud as where the world is going? What benefits does it bring? And how does Cisco connect all of these clouds? He also discussed Intercloud and Cisco’s investment on it.
17th Cloud Expo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises a...
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding bu...
There is no question that the cloud is where businesses want to host data. Until recently hypervisor virtualization was the most widely used method in cloud computing. Recently virtual containers have been gaining in popularity, and for good reason. In the debate between virtual machines and containers, the latter have been seen as the new kid on the block – and like other emerging technology have had some initial shortcomings. However, the container space has evolved drastically since coming on...
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover ...
Enterprises are fast realizing the importance of integrating SaaS/Cloud applications, API and on-premises data and processes, to unleash hidden value. This webinar explores how managers can use a Microservice-centric approach to aggressively tackle the unexpected new integration challenges posed by proliferation of cloud, mobile, social and big data projects. Industry analyst and SOA expert Jason Bloomberg will strip away the hype from microservices, and clearly identify their advantages and d...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading in...
The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential. The DevOps Summit at Cloud Expo – to be held June 3-5, 2015, at the Javits Center in New York City – will expand the DevOps community, enable a wide...
In her General Session at 15th Cloud Expo, Anne Plese, Senior Consultant, Cloud Product Marketing, at Verizon Enterprise, focused on finding the right mix of renting vs. buying Oracle capacity to scale to meet business demands, and offer validated Oracle database TCO models for Oracle development and testing environments. Anne Plese is a marketing and technology enthusiast/realist with over 19+ years in high tech. At Verizon Enterprise, she focuses on driving growth for the Verizon Cloud platfo...
Cloud Expo, Inc. has announced today that Andi Mann returns to DevOps Summit 2015 as Conference Chair. The 4th International DevOps Summit will take place on June 9-11, 2015, at the Javits Center in New York City. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited to help the great team at ...
How does one bridge the gap between traditional enterprise storage infrastructures and the private, hybrid, and public cloud? In his session at 15th Cloud Expo, Dan Pollack, Chief Architect of Storage Operations at AOL Inc., examed the workload differences and required changes to reuse existing knowledge and components when building and using a cloud infrastructure. He also looked into the operational considerations, tool requirements, and behavioral changes required for private cloud storage s...
Software is eating the world. Companies that were not previously in the technology space now find themselves competing with Google and Amazon on speed of innovation. As the innovation cycle accelerates, companies must embrace rapid and constant change to both applications and their infrastructure, and find a way to deliver speed and agility of development without sacrificing reliability or efficiency of operations. In her Day 2 Keynote DevOps Summit, Victoria Livschitz, CEO of Qubell, discussed...
The time is ripe for high speed resilient software defined storage solutions with unlimited scalability. ISS has been working with the leading open source projects and developed a commercial high performance solution that is able to grow forever without performance limitations. In his session at DevOps Summit, Alex Gorbachev, President of Intelligent Systems Services Inc., will share foundation principles of Ceph architecture, as well as the design to deliver this storage to traditional SAN st...
Gartner predicts that the bulk of new IT spending by 2016 will be for cloud platforms and applications and that nearly half of large enterprises will have cloud deployments by the end of 2017. The benefits of the cloud may be clear for applications that can tolerate brief periods of downtime, but for critical applications like SQL Server, Oracle and SAP, companies need a strategy for HA and DR protection. While traditional SAN-based clusters are not possible in these environments, SANless cluste...
Hardware will never be more valuable than on the day it hits your loading dock. Each day new servers are not deployed to production the business is losing money. While Moore's Law is typically cited to explain the exponential density growth of chips, a critical consequence of this is rapid depreciation of servers. The hardware for clustered systems (e.g., Hadoop, OpenStack) tends to be significant capital expenses. In his session at Big Data Expo, Mason Katz, CTO and co-founder of StackIQ, disc...
In a recent research, analyst firm IDC found that the average cost of a critical application failure is $500,000 to $1 million per hour and the average total cost of unplanned application downtime is $1.25 billion to $2.5 billion per year for Fortune 1000 companies. In addition to the findings on the cost of the downtime, the research also highlighted best practices for development, testing, application support, infrastructure, and operations teams.
In their general session at 16th Cloud Expo, Michael Piccininni, Global Account Manager – Cloud SP at EMC Corporation, and Mike Dietze, Regional Director at Windstream Hosted Solutions, will review next generation cloud services, including the Windstream-EMC Tier Storage solutions, and discuss how to increase efficiencies, improve service delivery and enhance corporate cloud solution development. Speaker Bios Michael Piccininni is Global Account Manager – Cloud SP at EMC Corporation. He has b...
All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo, June 9-11, 2015, at the Javits Center in New York City. Learn what is going on, contribute to the discussions, and ensure that your enter...