Welcome!

@CloudExpo Authors: Kevin Jackson, Liz McMillan, Yeshim Deniz, Pat Romanski, Jason Bloomberg

Related Topics: Containers Expo Blog, @CloudExpo

Containers Expo Blog: Article

Cloud Computing and Reliability

The Cloud offers some enticing advantages with respect to reliability

Eric Novikoff's Blog

IT managers and pundits speak of the reliability of a system in "nines." Two nines is the same as 99%, which comes to (100%-99%)*365 or 3.65 days of downtime per year, which is typical for non-redundant hardware if you include the time to reload the operating system and restore backups (if you have them) after a failure. Three nines is about 8 hours of downtime, four nines is about 52 minutes and the holy grail of 5 nines is 7 minutes.

From a users' point of view, downtime is downtime, but for a provider/vendor/web site manager, downtime is divided into planned and unplanned. Cloud computing can offer some benefits for planned downtime, but the place that it can have the largest effect on a business is in reducing unplanned downtime.

Planned downtime is usually the result of having to do some sort of software maintenance or release process, which is usually outside the domain of the cloud vendor, unless that vendor also offers IT operations services. Other sources of planned downtime are upgrades or scheduled equipment repairs. Most cloud vendors have some planned downtime, but because their business is based on providing high uptime, scheduled downtimes are kept to a minimum.

Unplanned downtime is where cloud vendors have the most to offer, and also the most to lose. Recent large outages at Amazon and Google have shown that even the largest cloud vendors can still have glitches that take considerable time to repair and give potential cloud customers a scare (perhaps it is because they didn't take some planned downtime??) On the other hand, cloud vendors have the experienced staff and proven processes that should produce overall hardware and network reliability that meets or exceeds that of the average corporate data center, and far exceeds anything you can achieve with colocated or self-managed servers.

However, despite claims of reliablity, few cloud vendors have tight SLAs (service level agreements) that promise controlled downtime or offer rebates for excess downtime. Amazon goes the opposite direction and doesn't offer any uptime guarantees, even cautioning users that their instance (or server) can disappear at any time and that they should plan accordingly. AppLogic-based clouds, provided by companies such as ENKI, are capable of offering better guarantees of uptime because of its inherent self-healing capabilities that can enable 3-4 nines of uptime. (The exact number depends on how the AppLogic system is set up and administered, which affects the time needed for the system to heal itself.) However, any cloud computing system, even even those based on AppLogic or similar technologies, can experience unplanned downtime for a variety of reasons, including the common culprit of human error. While I believe it is possible to produce a cloud computing service that exceeds 4-9s of uptime, the costs would be so high that few would buy it when they compared the price to the average cloud offering.


When you're purchasing cloud computing, it makes sense to look at the SLA of the vendor as well as the reliability of the underlying technology. But if your needs for uptime exceed that which the vendors and their technology can offer, there are time-honored techniques for improving it, most of which involve doubling the amount of computing nodes in your application. There's an old adage that each additional "9" of uptime you get doubles your cost, and that's because you need backup systems that are in place to take over if the primaries fail. This involves creating a system architecture for your application that allows for either active/passive failover (meaning that the backup nodes are running but not doing anything) or active/active failover (meaning that the backup nodes are normally providing application computing capability).

These solutions can be implemented in any cloud technology but they always require extra design and configuration effort for your application, and they should be tested rigorously to make sure they will work when the chips are down. Failover solutions are generally less expensive to implement in the Cloud because of the on-demand or pay-as-you go nature of cloud services, which means that you can easily size the backup server nodes to meet your needs and save on computing resources.

An important component of reliability is a good backup strategy. With cloud computing systems like AppLogic offering highly reliable storage as part of the package, many customers are tempted to skip backup. But data loss and the resulting unplanned downtime can result not just from failures in the cloud platform, but also software bugs, human error, or malfeasance such as hacking. If you don't have a backup, you'll be down a long time - and this applies equally to cloud and non-cloud solutions. The advantages of cloud solutions is that there is usually an inexpensive and large storage facility coupled with the cloud computing offering which gives you a convenient place to store your backups.

For the truly fanatical, backing up your data from one cloud vendor to another provides that extra measure of security. It pays to think through your backup strategy because most of today's backup software packages or remote backup services were designed for physical servers and not virtual environments having many virtual servers such as you might find in the cloud. This can mean very high software costs for doing backup if your backup software charges on a "per server" basis and your application is spread across many instances. If your cloud vendor has a backup offering, usually they have found a way to make backup affordable even if your application consists of many compute instances.

Another aspect of reliability that often escapes cloud computing customers new to the world of computing services is monitoring. It's very hard to react to unplanned downtime if you don't know your system is down. It's also hard to avoid unplanned downtime if you don't know you're about to run out of disk space or memory, or perhaps your application is complaining about data corruption. A remote monitoring service can scan your servers in the cloud on a regular basis for faults, application problems, or even measure the performance of your application (like how long it takes to buy a widget in your web store) and report to you if anything is out of the ordinary. I say "service" because if you were to install your own monitoring server into your cloud and the cloud went down, so would your monitoring! At ENKI, we solve this problem by having our monitoring service hosted in a separate data center and under a different software environment than our primary cloud hosting service.

The last aspect of reliability is security. However, that would require another entire article to cover, since security in the cloud is a complex and relatively new topic.

To sum up, the Cloud offers some enticing advantages with respect to reliability, perhaps the largest of which is that you can give your data center operations responsibility to someone who theoretically can do a much better job at a lower cost than you can. However, to get very good reliability, you must still apply traditional approaches of redundancy and observability that have been used in physical data centers for decades - or, you have to find a cloud computing services provider that can implement them for you.

More Stories By Eric Novikoff

Eric Novikoff is COO of ENKI, A Cloud Services Vendor. He has over 20 years of experience in the electronics and software industries, over a range of positions from integrated circuit designer to software/hardware project manager, to Director of Development at an Internet Software As A Service startup, Netsuite.com. His technical, project, and financial management skills have been honed in multiple positions at Hewlett-Packard and Agilent Technologies on a variety of product lines, including managing the development and roll-out of a worldwide CRM and sales automation application for Agilent's $350 million Automatic Test Equipment business. Novikoff also has a strong interest in SME (Small/Medium Size Enterprise) management, process development, and operations as a consequence of working at a web based ERP service startup serving SMEs, and through his small-business ERP consulting work.

Comments (1) View Comments

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.


Most Recent Comments
faseidl 09/10/08 11:45:52 AM EDT

Despite what many pundits have to say, reliability issues will not be the downfall of cloud computing. Using cloud computing does not mean neglecting to architect solutions that meet their business requirements, including reliability requirements.

I wrote more about this idea here:

Cloud Computing and Reliability
http://faseidl.com/public/item/212584

@CloudExpo Stories
SYS-CON Events announced today that Massive Networks will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Massive Networks mission is simple. To help your business operate seamlessly with fast, reliable, and secure internet and network solutions. Improve your customer's experience with outstanding connections to your cloud.
DX World EXPO, LLC., a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...
"The Striim platform is a full end-to-end streaming integration and analytics platform that is middleware that covers a lot of different use cases," explained Steve Wilkes, Founder and CTO at Striim, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
SYS-CON Events announced today that Calligo, an innovative cloud service provider offering mid-sized companies the highest levels of data privacy and security, has been named "Bronze Sponsor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Calligo offers unparalleled application performance guarantees, commercial flexibility and a personalised support service from its globally located cloud plat...
SYS-CON Events announced today that Calligo has been named “Bronze Sponsor” of SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Calligo is an innovative cloud service provider offering mid-sized companies the highest levels of data privacy. Calligo offers unparalleled application performance guarantees, commercial flexibility and a personalized support service from its globally located cloud platfor...
Everything run by electricity will eventually be connected to the Internet. Get ahead of the Internet of Things revolution and join Akvelon expert and IoT industry leader, Sergey Grebnov, in his session at @ThingsExpo, for an educational dive into the world of managing your home, workplace and all the devices they contain with the power of machine-based AI and intelligent Bot services for a completely streamlined experience.
21st International Cloud Expo, taking place October 31 - November 2, 2017, 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. Me...
"DX encompasses the continuing technology revolution, and is addressing society's most important issues throughout the entire $78 trillion 21st-century global economy," said Roger Strukhoff, Conference Chair. "DX World Expo has organized these issues along 10 tracks with more than 150 of the world's top speakers coming to Istanbul to help change the world."
SYS-CON Events announced today that DXWorldExpo has been named “Global Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Digital Transformation is the key issue driving the global enterprise IT business. Digital Transformation is most prominent among Global 2000 enterprises and government institutions.
SYS-CON Events announced today that Datera, that offers a radically new data management architecture, has been named "Exhibitor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Datera is transforming the traditional datacenter model through modern cloud simplicity. The technology industry is at another major inflection point. The rise of mobile, the Internet of Things, data storage and Big...
"With Digital Experience Monitoring what used to be a simple visit to a web page has exploded into app on phones, data from social media feeds, competitive benchmarking - these are all components that are only available because of some type of digital asset," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, 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.
"Outscale was founded in 2010, is based in France, is a strategic partner to Dassault Systémes and has done quite a bit of work with divisions of Dassault," explained Jackie Funk, Digital Marketing exec at Outscale, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
"DivvyCloud as a company set out to help customers automate solutions to the most common cloud problems," noted Jeremy Snyder, VP of Business Development at DivvyCloud, 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 the focus and objectives of IoT initiatives are many and diverse, they all share a few common attributes, and one of those is the network. Commonly, that network includes the Internet, over which there isn't any real control for performance and availability. Or is there? The current state of the art for Big Data analytics, as applied to network telemetry, offers new opportunities for improving and assuring operational integrity. In his session at @ThingsExpo, Jim Frey, Vice President of S...
"We focus on SAP workloads because they are among the most powerful but somewhat challenging workloads out there to take into public cloud," explained Swen Conrad, CEO of Ocean9, Inc., in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"As we've gone out into the public cloud we've seen that over time we may have lost a few things - we've lost control, we've given up cost to a certain extent, and then security, flexibility," explained Steve Conner, VP of Sales at Cloudistics,in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We are focused on SAP running in the clouds, to make this super easy because we believe in the tremendous value of those powerful worlds - SAP and the cloud," explained Frank Stienhans, CTO of Ocean9, Inc., in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"Peak 10 is a hybrid infrastructure provider across the nation. We are in the thick of things when it comes to hybrid IT," explained , Chief Technology Officer at Peak 10, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.