Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: Java IoT, Microservices Expo, ColdFusion, Microsoft Cloud, Machine Learning

Java IoT: Article

Load Testing in Clustered Environments

Clustered Environments: Load Testing for Architectural Validation (P.S. Don’t Extrapolate!)

Load and performance testing web applications will allow you to determine whether or not your deployment will require a clustered environment. When the test results show that the current throughput is restricted by the capacity of the server but target workloads are not yet met, this is a situation where you can achieve higher scalability by implementing clusters to your environment. Clustering achieves higher scalability by introducing more servers or nodes to expand the capacity of the environment. Obviously, the benefits of adding hardware include higher capacity, reliability, availability, and scalability. But also consider that clustering also adds complexity to your deployment by requiring added maintenance and an increased need for deployment/upgrade automation. To ensure quality of the environment you must always validate your clustered environment and prove out the increased scalability. Use a methodical performance testing approach. Don't try to extrapolate! It's not as easy as "3 nodes in a cluster will support 3x the workload."

Why Cluster?
An efficiently tuned deployment will, in turn, display an efficient use of server resources (memory, CPU, i/o, etc). Using a cluster increases the number of servers and distributes the workload amongst several servers. This even distribution of the workload can dramatically increase scalability. Not only can this improve the end user experience by reaching higher workloads with predictable response times but it can increase the reliability and stability of the deployment. The cluster acts as a single server so the loss or shutdown of any of the nodes in the cluster will not result in loss of sessions or application data. In the end, the user experience is less frequently interrupted and isn't affected by a single maxed out server or a loss of a server.

Tuning Tips
When performance or load testing your application uncovers a clear need to introduce clusters or farms to support the target workload, you will want to take into account the following considerations: First you should configure the cluster efficiently for internal maintenance such as data synchronization and heartbeat communications. User sessions which live in memory are more quickly failed over to another node in the cluster instead of persisting them to the database. However, writing the sessions to disk is more permanent which may have its own advantages. Make sure you have tested the performance prices for data synchronization and heartbeat communications. The goal is to configure the cluster to increase scalability with as little overhead as possible.

Load Balancers
Load balancers are generally placed out in front of the clusters. These load balancers can be a software solution or a hardware solution. Their job is to distribute the load evenly to the nodes in the cluster. Just as important, LB's reroute traffic when one node of the cluster goes down. This allows for the "transparency" of several servers acting as one. There are several more mature algorithms for distribution than traditional "round robins." Smarter LB's takes into account the CPU and resource usage and overall load of each server and their job is to direct the request to the least loaded server. The number of active users doesn't always equate to more resources being actively used, rather it depends on the types of transactions being executed - lightweight vs. expensive transactions. Smart LB's will detect workload and direct incoming traffic based on resource usage. Often LB's will use sticky sessions based on the client's cookie and/or IP address to route subsequent requests to the same node of cluster where the user session lives. Whenload testing these types of environments, it's a requirement to have a load tool which supports IP Spoofing. This is used to generate the load of many virtual users using multiple IP addresses all from a single machine. Otherwise, the total load would go to a single cluster node.

Types of Clustering
Clustering can be achieved using a few common techniques. Vertical clustering adds capacity to the deployment by installing multiple nodes of a cluster on a single machine. With this approach you must take into consideration the physical limitations of that machine (CPU, memory, i/o) and be careful not over utilize resources; otherwise adding more nodes becomes pointless due to saturation. Horizontal clusters refer to deploying more physical machines. With this approach, each physical machine can run one or more of the nodes of the cluster. Cloud bursting is a way of having a node both within the LAN and a node in the Cloud to be turned "on" during high volume usage or be strategically placed in different geographical locations. The appropriate technique really depends on the specifics of your environment. If you need more capacity and you have beefy infrastructure servers but do not have enough web servers or app servers to fully utilize the underlying hardware, choose the vertical clustering approach by adding more nodes to the same machine. On the other hand, if more physical resources are needed to handle the workload, then build out a horizontal cluster by adding more hardware and deploying more nodes.

How to Load Test a Cluster?
It's important to take a methodical approach to load testing a clustered environment. Load patterns such as ramping tests allow you to identify the current capacity as well as increased scalability as you add more nodes to the cluster. Remember that doubling the number of nodes in a cluster does not equate to doubling its capacity. Many components impact its performance gain such as the communications between the nodes used to just make the cluster work properly. The resource cost increases dramatically with the number of nodes. Capacity is relative and is dependent on myriad other components within the infrastructure. For example, adding another node to the cluster may give the application layer 2x the throughput (although this is not really possible due to "housekeeping" from internal administration overhead to maintain that cluster), but let's say the single webserver out front is already using all its worker threads, then requests will be queued while waiting for a thread to become available and overall throughput will not increase. Only through the analysis of load test results will you completely understand the increased scalability effects of a cluster. Consider another scenario: You have identified a need for building out a cluster of application servers, however you deploy too many nodes resulting in a backlog of requests on the shared database. Performance and load testing will uncover this vulnerability and many other potential scenarios that could otherwise go undetected. Having a comparison analysis feature built right into the load tool will allow you to run tests back to back, after turning on/off nodes in the cluster, and quickly visualize the differences. Also, having the tool with a built-in cloud load generation feature will save time and money setting up and maintaining the performance architecture environment, especially for high load tests.

The Right Approach?
Adding clustering to a deployment allows a web application to achieve higher workloads and gives the advantage of higher availability. However, you must conduct performance tests in order to build out an efficient cluster which meets your goals. Don't forget to weigh the benefits vs. added maintenance complexity/cost. Clusters require a high level of expertise to implement and maintain so they aren't the best solution in every situation. Make sure all moving parts are documented and insist on a complete architectural diagram for future systems administrators (diagrams to include hierarchical transaction pathways as well as location of each node in the cluster including the admin consoles). In the end it's all about delivering the best possible end user experience and in many cases clustering is an excellent solution for increasing scalability of your web deployments.

More Stories By Rebecca Clinard

Rebecca Clinard is a Senior Performance Engineer at Neotys, a provider of load testing software for Web applications. Previously, she worked as a web application performance engineer for Bowstreet, Fidelity Investments, Bottomline Technologies and Timberland companies, industries spanning retail, financial services, insurance and manufacturing. Her expertise lies in creating realistic load tests and performance tuning multi-tier deployments. She has been orchestrating and conducting performance tests since 2001. Clinard graduated from University of New Hampshire with a BS and also holds a UNIX Certificate from Worcester Polytechnic Institute.

@ThingsExpo Stories
Real IoT production deployments running at scale are collecting sensor data from hundreds / thousands / millions of devices. The goal is to take business-critical actions on the real-time data and find insights from stored datasets. In his session at @ThingsExpo, John Walicki, Watson IoT Developer Advocate at IBM Cloud, will provide a fast-paced developer journey that follows the IoT sensor data from generation, to edge gateway, to edge analytics, to encryption, to the IBM Bluemix cloud, to Wa...
What is the best strategy for selecting the right offshore company for your business? In his session at 21st Cloud Expo, Alan Winters, U.S. Head of Business Development at MobiDev, will discuss the things to look for - positive and negative - in evaluating your options. He will also discuss how to maximize productivity with your offshore developers. Before you start your search, clearly understand your business needs and how that impacts software choices.
SYS-CON Events announced today that Massive Networks, that helps your business operate seamlessly with fast, reliable, and secure internet and network solutions, 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. As a premier telecommunications provider, Massive Networks is headquartered out of Louisville, Colorado. With years of experience under their belt, their team of...
SYS-CON Events announced today that Fusic will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Fusic Co. provides mocks as virtual IoT devices. You can customize mocks, and get any amount of data at any time in your test. For more information, visit https://fusic.co.jp/english/.
SYS-CON Events announced today that MIRAI Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. MIRAI Inc. are IT consultants from the public sector whose mission is to solve social issues by technology and innovation and to create a meaningful future for people.
SYS-CON Events announced today that Enroute Lab will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Enroute Lab is an industrial design, research and development company of unmanned robotic vehicle system. For more information, please visit http://elab.co.jp/.
SYS-CON Events announced today that Mobile Create USA will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Mobile Create USA Inc. is an MVNO-based business model that uses portable communication devices and cellular-based infrastructure in the development, sales, operation and mobile communications systems incorporating GPS capabi...
There is huge complexity in implementing a successful digital business that requires efficient on-premise and cloud back-end infrastructure, IT and Internet of Things (IoT) data, analytics, Machine Learning, Artificial Intelligence (AI) and Digital Applications. In the data center alone, there are physical and virtual infrastructures, multiple operating systems, multiple applications and new and emerging business and technological paradigms such as cloud computing and XaaS. And then there are pe...
SYS-CON Events announced today that Interface Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Interface Corporation is a company developing, manufacturing and marketing high quality and wide variety of industrial computers and interface modules such as PCIs and PCI express. For more information, visit http://www.i...
SYS-CON Events announced today that Keisoku Research Consultant Co. will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Keisoku Research Consultant, Co. offers research and consulting in a wide range of civil engineering-related fields from information construction to preservation of cultural properties. For more information, vi...
SYS-CON Events announced today that SIGMA Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. uLaser flow inspection device from the Japanese top share to Global Standard! Then, make the best use of data to flip to next page. For more information, visit http://www.sigma-k.co.jp/en/.
SYS-CON Events announced today that B2Cloud 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. B2Cloud specializes in IoT devices for preventive and predictive maintenance in any kind of equipment retrieving data like Energy consumption, working time, temperature, humidity, pressure, etc.
Agile has finally jumped the technology shark, expanding outside the software world. Enterprises are now increasingly adopting Agile practices across their organizations in order to successfully navigate the disruptive waters that threaten to drown them. In our quest for establishing change as a core competency in our organizations, this business-centric notion of Agile is an essential component of Agile Digital Transformation. In the years since the publication of the Agile Manifesto, the conn...
While some developers care passionately about how data centers and clouds are architected, for most, it is only the end result that matters. To the majority of companies, technology exists to solve a business problem, and only delivers value when it is solving that problem. 2017 brings the mainstream adoption of containers for production workloads. In his session at 21st Cloud Expo, Ben McCormack, VP of Operations at Evernote, will discuss how data centers of the future will be managed, how th...
SYS-CON Events announced today that NetApp 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. NetApp is the data authority for hybrid cloud. NetApp provides a full range of hybrid cloud data services that simplify management of applications and data across cloud and on-premises environments to accelerate digital transformation. Together with their partners, NetApp em...
SYS-CON Events announced today that Nihon Micron will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Nihon Micron Co., Ltd. strives for technological innovation to establish high-density, high-precision processing technology for providing printed circuit board and metal mount RFID tags used for communication devices. For more inf...
SYS-CON Events announced today that Suzuki Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Suzuki Inc. is a semiconductor-related business, including sales of consuming parts, parts repair, and maintenance for semiconductor manufacturing machines, etc. It is also a health care business providing experimental research for...
SYS-CON Events announced today that Ryobi Systems will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Ryobi Systems Co., Ltd., as an information service company, specialized in business support for local governments and medical industry. We are challenging to achive the precision farming with AI. For more information, visit http:...
SYS-CON Events announced today that Daiya Industry will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Daiya Industry specializes in orthotic support systems and assistive devices with pneumatic artificial muscles in order to contribute to an extended healthy life expectancy. For more information, please visit https://www.daiyak...
In his session at @ThingsExpo, Greg Gorman is the Director, IoT Developer Ecosystem, Watson IoT, will provide a short tutorial on Node-RED, a Node.js-based programming tool for wiring together hardware devices, APIs and online services in new and interesting ways. It provides a browser-based editor that makes it easy to wire together flows using a wide range of nodes in the palette that can be deployed to its runtime in a single-click. There is a large library of contributed nodes that help so...