|By Rebecca Clinard||
|September 17, 2012 05:00 AM EDT||
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."
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.
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 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.
SYS-CON Events announced today that China Unicom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. China United Network Communications Group Co. Ltd ("China Unicom") was officially established in 2009 on the basis of the merger of former China Netcom and former China Unicom. China Unicom mainly operates a full range of telecommunications services including mobile broadband (GSM, WCDMA, LTE F...
Sep. 26, 2016 11:15 AM EDT Reads: 1,725
SYS-CON Events announced today the Enterprise IoT Bootcamp, being held November 1-2, 2016, in conjunction with 19th Cloud Expo | @ThingsExpo at the Santa Clara Convention Center in Santa Clara, CA. Combined with real-world scenarios and use cases, the Enterprise IoT Bootcamp is not just based on presentations but with hands-on demos and detailed walkthroughs. We will introduce you to a variety of real world use cases prototyped using Arduino, Raspberry Pi, BeagleBone, Spark, and Intel Edison. Y...
Sep. 26, 2016 11:15 AM EDT Reads: 2,858
Major trends and emerging technologies – from virtual reality and IoT, to Big Data and algorithms – are helping organizations innovate in the digital era. However, to create real business value, IT must think beyond the ‘what’ of digital transformation to the ‘how’ to harness emerging trends, innovation and disruption. Architecture is the key that underpins and ties all these efforts together. In the digital age, it’s important to invest in architecture, extend the enterprise footprint to the cl...
Sep. 26, 2016 11:06 AM EDT
Video experiences should be unique and exciting! But that doesn’t mean you need to patch all the pieces yourself. Users demand rich and engaging experiences and new ways to connect with you. But creating robust video applications at scale can be complicated, time-consuming and expensive. In his session at @ThingsExpo, Zohar Babin, Vice President of Platform, Ecosystem and Community at Kaltura, will discuss how VPaaS enables you to move fast, creating scalable video experiences that reach your...
Sep. 26, 2016 11:00 AM EDT Reads: 984
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
Sep. 26, 2016 10:45 AM EDT Reads: 3,211
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. 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 dev...
Sep. 26, 2016 10:45 AM EDT Reads: 3,405
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
Sep. 26, 2016 10:30 AM EDT Reads: 888
SYS-CON Events announced today that Bsquare has been named “Silver Sponsor” of SYS-CON's @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. For more than two decades, Bsquare has helped its customers extract business value from a broad array of physical assets by making them intelligent, connecting them, and using the data they generate to optimize business processes.
Sep. 26, 2016 10:00 AM EDT Reads: 2,678
SYS-CON Events announced today that ReadyTalk, a leading provider of online conferencing and webinar services, has been named Vendor Presentation Sponsor at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. ReadyTalk delivers audio and web conferencing services that inspire collaboration and enable the Future of Work for today’s increasingly digital and mobile workforce. By combining intuitive, innovative tec...
Sep. 26, 2016 10:00 AM EDT Reads: 2,755
Big Data has been changing the world. IoT fuels the further transformation recently. How are Big Data and IoT related? In his session at @BigDataExpo, Tony Shan, a renowned visionary and thought leader, will explore the interplay of Big Data and IoT. He will anatomize Big Data and IoT separately in terms of what, which, why, where, when, who, how and how much. He will then analyze the relationship between IoT and Big Data, specifically the drilldown of how the 4Vs of Big Data (Volume, Variety,...
Sep. 26, 2016 10:00 AM EDT Reads: 1,002
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
Sep. 26, 2016 09:45 AM EDT Reads: 2,837
WebRTC adoption has generated a wave of creative uses of communications and collaboration through websites, sales apps, customer care and business applications. As WebRTC has become more mainstream it has evolved to use cases beyond the original peer-to-peer case, which has led to a repeating requirement for interoperability with existing infrastructures. In his session at @ThingsExpo, Graham Holt, Executive Vice President of Daitan Group, will cover implementation examples that have enabled ea...
Sep. 26, 2016 09:00 AM EDT Reads: 1,525
Vidyo, Inc., has joined the Alliance for Open Media. The Alliance for Open Media is a non-profit organization working to define and develop media technologies that address the need for an open standard for video compression and delivery over the web. As a member of the Alliance, Vidyo will collaborate with industry leaders in pursuit of an open and royalty-free AOMedia Video codec, AV1. Vidyo’s contributions to the organization will bring to bear its long history of expertise in codec technolo...
Sep. 26, 2016 08:15 AM EDT Reads: 2,466
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management solutions, helping companies worldwide activate their data to drive more value and business insight and to transform moder...
Sep. 26, 2016 08:15 AM EDT Reads: 2,547
The vision of a connected smart home is becoming reality with the application of integrated wireless technologies in devices and appliances. The use of standardized and TCP/IP networked wireless technologies in line-powered and battery operated sensors and controls has led to the adoption of radios in the 2.4GHz band, including Wi-Fi, BT/BLE and 802.15.4 applied ZigBee and Thread. This is driving the need for robust wireless coexistence for multiple radios to ensure throughput performance and th...
Sep. 26, 2016 08:15 AM EDT Reads: 1,544
An IoT product’s log files speak volumes about what’s happening with your products in the field, pinpointing current and potential issues, and enabling you to predict failures and save millions of dollars in inventory. But until recently, no one knew how to listen. In his session at @ThingsExpo, Dan Gettens, Chief Research Officer at OnProcess, will discuss recent research by Massachusetts Institute of Technology and OnProcess Technology, where MIT created a new, breakthrough analytics model f...
Sep. 26, 2016 07:15 AM EDT Reads: 1,905
If you’re responsible for an application that depends on the data or functionality of various IoT endpoints – either sensors or devices – your brand reputation depends on the security, reliability, and compliance of its many integrated parts. If your application fails to deliver the expected business results, your customers and partners won't care if that failure stems from the code you developed or from a component that you integrated. What can you do to ensure that the endpoints work as expect...
Sep. 26, 2016 07:15 AM EDT Reads: 1,605
Technology vendors and analysts are eager to paint a rosy picture of how wonderful IoT is and why your deployment will be great with the use of their products and services. While it is easy to showcase successful IoT solutions, identifying IoT systems that missed the mark or failed can often provide more in the way of key lessons learned. In his session at @ThingsExpo, Peter Vanderminden, Principal Industry Analyst for IoT & Digital Supply Chain to Flatiron Strategies, will focus on how IoT de...
Sep. 26, 2016 06:45 AM EDT Reads: 1,085
Fact is, enterprises have significant legacy voice infrastructure that’s costly to replace with pure IP solutions. How can we bring this analog infrastructure into our shiny new cloud applications? There are proven methods to bind both legacy voice applications and traditional PSTN audio into cloud-based applications and services at a carrier scale. Some of the most successful implementations leverage WebRTC, WebSockets, SIP and other open source technologies. In his session at @ThingsExpo, Da...
Sep. 26, 2016 06:30 AM EDT Reads: 1,571
SYS-CON Events announced today that Roundee / LinearHub will exhibit at the WebRTC Summit at @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LinearHub provides Roundee Service, a smart platform for enterprise video conferencing with enhanced features such as automatic recording and transcription service. Slack users can integrate Roundee to their team via Slack’s App Directory, and '/roundee' command lets your video conference ...
Sep. 26, 2016 04:30 AM EDT Reads: 1,423