Welcome!

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.


Latest Stories
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
"We got started as search consultants. On the services side of the business we have help organizations save time and save money when they hit issues that everyone more or less hits when their data grows," noted Otis Gospodnetić, Founder of Sematext, in this SYS-CON.tv interview at @DevOpsSummit, held June 9-11, 2015, at the Javits Center in New York City.
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. 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 June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
It is one thing to build single industrial IoT applications, but what will it take to build the Smart Cities and truly society changing applications of the future? The technology won’t be the problem, it will be the number of parties that need to work together and be aligned in their motivation to succeed. In his Day 2 Keynote at @ThingsExpo, Henrik Kenani Dahlgren, Portfolio Marketing Manager at Ericsson, discussed how to plan to cooperate, partner, and form lasting all-star teams to change the...
For organizations that have amassed large sums of software complexity, taking a microservices approach is the first step toward DevOps and continuous improvement / development. Integrating system-level analysis with microservices makes it easier to change and add functionality to applications at any time without the increase of risk. Before you start big transformation projects or a cloud migration, make sure these changes won’t take down your entire organization.
SYS-CON Events announced today that delaPlex will exhibit at SYS-CON's @CloudExpo, 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.
SYS-CON Events announced today that IoT Now has been named “Media 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. IoT Now explores the evolving opportunities and challenges facing CSPs, and it passes on some lessons learned from those who have taken the first steps in next-gen IoT services.
Updating DevOps to the latest production data slows down your development cycle. Probably it is due to slow, inefficient conventional storage and associated copy data management practices. In his session at @DevOpsSummit at 20th Cloud Expo, Dhiraj Sehgal, in Product and Solution at Tintri, will talk about DevOps and cloud-focused storage to update hundreds of child VMs (different flavors) with updates from a master VM in minutes, saving hours or even days in each development cycle. He will also...
Extreme Computing is the ability to leverage highly performant infrastructure and software to accelerate Big Data, machine learning, HPC, and Enterprise applications. High IOPS Storage, low-latency networks, in-memory databases, GPUs and other parallel accelerators are being used to achieve faster results and help businesses make better decisions. In his session at 18th Cloud Expo, Michael O'Neill, Strategic Business Development at NVIDIA, focused on some of the unique ways extreme computing is...
The explosion of new web/cloud/IoT-based applications and the data they generate are transforming our world right before our eyes. In this rush to adopt these new technologies, organizations are often ignoring fundamental questions concerning who owns the data and failing to ask for permission to conduct invasive surveillance of their customers. Organizations that are not transparent about how their systems gather data telemetry without offering shared data ownership risk product rejection, regu...
SYS-CON Events announced today that WineSOFT 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. Based in Seoul and Irvine, WineSOFT is an innovative software house focusing on internet infrastructure solutions. The venture started as a bootstrap start-up in 2010 by focusing on making the internet faster and more powerful. WineSOFT’s knowledge is based on the expertise of TCP/IP, VPN, SSL, peer-to-peer, mob...
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, discussed the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports.
With billions of sensors deployed worldwide, the amount of machine-generated data will soon exceed what our networks can handle. But consumers and businesses will expect seamless experiences and real-time responsiveness. What does this mean for IoT devices and the infrastructure that supports them? More of the data will need to be handled at - or closer to - the devices themselves.
SYS-CON Events announced today that Dataloop.IO, an innovator in cloud IT-monitoring whose products help organizations save time and money, 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. Dataloop.IO is an emerging software company on the cutting edge of major IT-infrastructure trends including cloud computing and microservices. The company, founded in the UK but now based in San Fran...
Big Data, cloud, analytics, contextual information, wearable tech, sensors, mobility, and WebRTC: together, these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at @ThingsExpo, Erik Perotti, Senior Manager of New Ventures on Plantronics’ Innovation team, provided an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it m...