Welcome!

SDN Journal Authors: Liz McMillan, Hollis Tibbetts, Vinod Mohan, Chris Colosimo, Jason Bloomberg

Related Topics: @CloudExpo, Java IoT, Microservices Expo, Linux Containers, Cloud Security, SDN Journal

@CloudExpo: Article

The Facts About Cloud High Availability and Disaster Recovery

Understanding the facts about HA and DR in the cloud can help you make informed decisions

Enterprises are moving more and more applications to the cloud. Gartner predicts that the bulk of new IT spending by 2016 will be for cloud computing platforms and applications and that nearly half of large enterprises will have cloud deployments by the end of 2017.1

The far-reaching impact of cloud computing is summarized in a recent McKinsey report on disruptive technologies: "Cloud technology has the potential to improve productivity across $3 trillion in global enterprise IT spending, as well as enabling the creation of new online products and services for billions of consumers and millions of businesses alike."2

For many organizations, moving applications that can tolerate brief periods of downtime to the cloud is a straightforward decision with clear benefits. However, concerns about how to provide high availability and disaster protection in the cloud may make this decision more difficult for business-critical applications such as SQL, SAP, and Exchange. Understanding the facts about HA and DR in the cloud can help you make informed decisions about moving applications to the cloud, while ensuring the important business operations that depend on them are protected from downtime and data loss.

Fact #1: You need high availability protection in a cloud.
Do not assume that your cloud environment provides high availability protection, unless you have specifically configured it for HA. In fact, according to a recent study: "The average unavailability of cloud services is 10 hours per year or more, while the average availability is estimated to be 99.9% far less than the expected availability of business critical applications."3 That is the equivalent of more than a day of downtime. In fact, in 2014, Microsoft Windows Azure, Google, and Amazon Web Services all had some measure of service interruptions or downtime ranging from 4 minutes to several hours.4

For business critical applications, the redundancy that you can get with some cloud solutions, such as Windows Azure, is not enough. When you consider the cost of a minute of downtime for applications, such as SQL Server, Oracle, and SAP that may run many of your key business processes, it becomes clear that you need true high availability and disaster recovery protection. You need to ensure that end users have immediate access to data and applications in the event of a local failure, a regional disaster or anything in between.

However, the traditional way of providing high availability protection is to build a cluster using two identical servers - a primary server and a standby server -  with shared (typically SAN) storage. If the primary server fails, the application operation is moved to the standby server, which has immediate access to the same storage. The problem is that SANs are not only expensive to buy, manage, and maintain, they are simply not an option in public cloud offerings. There are, however, high availability solutions that can be used in a cloud that do not require a SAN.

Fact #2: You can build a cluster in a cloud.
Even though you cannot have a SAN in a cloud, you can build a cluster for high availability protection. In a Windows cloud, you simply add SANLess cluster software to your Windows Server Failover Cluster (WSFC). The SANLess software uses real time, block level replication to keep local storage in two geographic regions of the cloud synchronized. If there is an outage, the application operation is automatically moved to the remote instance, which has immediate access to current data. The synchronized storage looks to the WSFC like a traditional shared storage so there is no added complexity or specialized skills needed to build or manage a SANLess cluster. In fact, a SANLess cluster is easy to manage and has the added benefit of eliminating the single point of failure risk of a SAN. SANLess clusters also provide complete configuration flexibility, allowing you to replicate between physical, virtual, cloud, and hybrid cloud environment as well as between SAN and SANLess clusters.

Fact #3: You can have geographically separated nodes for DR in a cloud.
While providing high availability within the cloud will protect you from normal hardware failures and other unexpected outages within an availability zone (Amazon) or fault domain (Azure), you still need to protect against regional disasters. The easiest solution is to configure a multisite (geographically separated) cluster.

One effective method is to build a SANLess cluster within a cloud and extend it for disaster recovery by adding another node(s) in an alternate data center or a different geographic region within the cloud. Unlike traditional clusters that require you to have identical hardware and software in every node, a SANLess cluster allows you to mix physical, cloud and hybrid cloud configurations. The benefits of a DR configuration are clear. For example, simply adding a third, geographically separated node to your SANLess cluster in a Windows Azure cloud can give you a recovery point objective (RPO) of near zero data loss and a recovery time objective (RTO) of just about one minute.

Fact #4: You can create a cluster that mixes cloud and on-premises nodes.
You can use your on-premises data center as your primary location with a failover cluster to provide high availability protection and use the cloud as your hot standby DR site. This is a very cost-effective alternative to building out your own DR site, or renting rack space in a business continuity facility. In this case, the on-premises servers can be your choice of traditional SAN-based clusters, SANLess clusters, or even single servers not currently participating in a cluster.

The objective of having a "hot" standby DR site is to have standby servers up and running as quickly as possible in the DR site with access to a copy of the most recent application data. In the event of a disaster, recovery is automatic and immediate. A multisite cluster is an effective way to implement a hot standby DR site. In this case, the SANLess date. In the event of a forecasted disaster, such as a storm or a flood, applications can be moved to the cloud before potential disaster strikes. In the event of an unexpected disaster, applications can be recovered manually or in some cases automatically, depending upon the quorum configuration. This mix of cloud and on-premises nodes gives you an excellent RTO and RPO with minimal investment in infrastructure.

Fact #5: HA and DR in a cloud can be easy and highly cost-effective.
If you choose a SANLess software that provides an intuitive configuration interface, you can create a standard WSFC in a cloud in minutes without specialized skills. A SANLess cluster can help you realize significant cost savings in several ways. First, in a Microsoft SQL Server environment a SANLess cluster can give you high availability with SQL Server Standard Edition software licenses without requiring you to upgrade to costly SQL Server Enterprise Edition.

Second, you can realize hundreds of thousands of dollars in savings with a SANLess by eliminating the total cost of ownership (TCO) associated with a SAN. The savings in TCO include the SAN hardware acquisition costs; the power, cooling, and data center floor space costs; and the ongoing labor cost of specialized SAN administration.

If you are thinking about moving your important applications to the cloud, you need to consider how you will protect those applications from downtime and data loss. While traditional SAN-based clusters are not possible in these environments, SANLess clusters can provide an easy, cost-efficient alternative. These clusters not only provide high availability protection, but also enable significantly greater configuration flexibility and potentially dramatic savings in both licensing costs and SAN TCO.

Notes

1"Gartner Says Cloud Computing Will Become the Bulk of New IT Spend by 2016."

2 Manyika, James and Michael Chui, et al, "Disruptive technologies: Advances that will transform life, business, and the global economy," McKinsey Global Institute (May 2013) 

3Whittaker, Josh, "Amazon Web Services Suffers Outage, Takes Out Vine, Instagram, Others with it," ZDNet, (August 26, 2013)

4Mackay, Martin, "Downtime Report: Top Ten Outages in 2013," Business2Community.com, (December 2013)

More Stories By Jerry Melnick

Jerry Melnick ([email protected]) is responsible for defining corporate strategy and operations at SIOS Technology Corp. (www.us.sios.com), maker of SIOS SAN and #SANLess cluster software (www.clustersyourway.com). He more than 25 years of experience in the enterprise and high availability software industries. He holds a Bachelor of Science degree from Beloit College with graduate work in Computer Engineering and Computer Science at Boston University.

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
IBM helps FinTechs and financial services companies build and monetize cognitive-enabled financial services apps quickly and at scale. Hosted on IBM Bluemix, IBM’s platform builds in customer insights, regulatory compliance analytics and security to help reduce development time and testing. In his session at 20th Cloud Expo, Tom Eck, Industry Platforms CTO at IBM Cloud, will discuss how these tools simplify the time-consuming tasks of selection, mapping and data integration, allowing developers ...
SYS-CON Events announced today that Outscale, a global pure play Infrastructure as a Service provider and strategic partner of Dassault Systèmes, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2010, Outscale simplifies infrastructure complexities and boosts the business agility of its customers. Outscale delivers a secure, reliable and industrial strength solution for its customers, which in...
SYS-CON Events announced today that Progress, a global leader in application development, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Enterprises today are rapidly adopting the cloud, while continuing to retain business-critical/sensitive data inside the firewall. This is creating two separate data silos – one inside the firewall and the other outside the firewall. Cloud ISVs oft...
Regardless of what business you’re in, it’s increasingly a software-driven business. Consumers’ rising expectations for connected digital and physical experiences are driving what some are calling the "Customer Experience Challenge.” In his session at @DevOpsSummit at 20th Cloud Expo, Marco Morales, Director of Global Solutions at CollabNet, will discuss how organizations are increasingly adopting a discipline of Value Stream Mapping to ensure that the software they are producing is poised to o...
Interested in leveling up on your Cloud Foundry skills? Join IBM for Cloud Foundry Days on June 7 at Cloud Expo New York at the Javits Center in New York City. Cloud Foundry Days is a free half day educational conference and networking event. Come find out why Cloud Foundry is the industry's fastest-growing and most adopted cloud application platform.
In order to meet the rapidly changing demands of today’s customers, companies are continually forced to redefine their business strategies in order to meet these needs, stay relevant and continue to see profitable growth. IoT deployment and development is integral in this transformation, and today businesses are increasingly seeing the value of investing their resources into IoT deployments. These technologies are able increase ROI through projects such as connecting supply chains or enabling sm...
Most DevOps journeys involve several phases of maturity. Research shows that the inflection point where organizations begin to see maximum value is when they implement tight integration deploying their code to their infrastructure. Success at this level is the last barrier to at-will deployment. Storage, for instance, is more capable than where we read and write data. In his session at @DevOpsSummit at 20th Cloud Expo, Josh Atwell, a Developer Advocate for NetApp, will discuss the role and value...
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Ge...
When NSA's digital armory was leaked, it was only a matter of time before the code was morphed into a ransom seeking worm. This talk, designed for C-level attendees, demonstrates a Live Hack of a virtual environment to show the ease in which any average user can leverage these tools and infiltrate their network environment. This session will include an overview of the Shadbrokers NSA leak situation.
As cloud adoption continues to transform business, today's global enterprises are challenged with managing a growing amount of information living outside of the data center. The rapid adoption of IoT and increasingly mobile workforce are exacerbating the problem. Ensuring secure data sharing and efficient backup poses capacity and bandwidth considerations as well as policy and regulatory compliance issues.
SYS-CON Events announced today that Interoute has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Interoute is the owner operator of Europe's largest network and a global cloud services platform, which encompasses over 70,000 km of lit fiber, 15 data centers, 17 virtual data centers and 33 colocation centers, with connections to 195 additional partner data centers. Our full-service Unifie...
SYS-CON Events announced today that delaPlex will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. delaPlex pioneered Software Development as a Service (SDaaS), which provides scalable resources to build, test, and deploy software. It’s a fast and more reliable way to develop a new product or expand your in-house team.
In his opening keynote at 20th Cloud Expo, Michael Maximilien, Research Scientist, Architect, and Engineer at IBM, will motivate why realizing the full potential of the cloud and social data requires artificial intelligence. By mixing Cloud Foundry and the rich set of Watson services, IBM's Bluemix is the best cloud operating system for enterprises today, providing rapid development and deployment of applications that can take advantage of the rich catalog of Watson services to help drive insigh...
Amazon started as an online bookseller 20 years ago. Since then, it has evolved into a technology juggernaut that has disrupted multiple markets and industries and touches many aspects of our lives. It is a relentless technology and business model innovator driving disruption throughout numerous ecosystems. Amazon’s AWS revenues alone are approaching $16B a year making it one of the largest IT companies in the world. With dominant offerings in Cloud, IoT, eCommerce, Big Data, AI, Digital Assis...
The 21st International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Machine Learning 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 busin...
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo Silicon Valley Call for Papers is now open.
For financial firms, the cloud is going to increasingly become a crucial part of dealing with customers over the next five years and beyond, particularly with the growing use and acceptance of virtual currencies. There are new data storage paradigms on the horizon that will deliver secure solutions for storing and moving sensitive financial data around the world without touching terrestrial networks. In his session at 20th Cloud Expo, Cliff Beek, President of Cloud Constellation Corporation, w...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In his Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, will explore t...
As enterprise cloud becomes the norm, businesses and government programs must address compounded regulatory compliance related to data privacy and information protection. The most recent, Controlled Unclassified Information and the EU’s GDPR have board level implications and companies still struggle with demonstrating due diligence. Developers and DevOps leaders, as part of the pre-planning process and the associated supply chain, could benefit from updating their code libraries and design by in...
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.