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Elasticity – generally refers to increasing or decreasing cloud resources. An elastic system automatically adapts to match resources with demand as closely as possible, in real time. Scalability is the ability of a system to be able to support increased processing/traffic by increasing a system’s resources or increasing the number of systems supporting the process .
It refers to the system environment’s ability to use as many resources as required. One exception is that if elastic requirements can be predicted, then autoscaling can be effectively applied. First of all, the principle of autoscaling is to track specific metrics by sampling and start scaling when the threshold is exceeded for a period of time.
But cloud elasticity and cloud scalability are still considered equal. Elasticity is the ability to fit the resources needed to cope with loads dynamically usually in relation to scale out. So that when the load increases you scale by adding more resources and when demand wanes you shrink back and remove unneeded resources. Thanks to the pay-per-use pricing model of modern cloud platforms, cloud elasticity is a cost-effective solution for businesses with a dynamic workload like streaming services or e-commerce marketplaces. It’s more flexible and cost-effective as it helps add or remove resources as per existing workload requirements. Adding and upgrading resources according to the varying system load and demand provides better throughput and optimizes resources for even better performance.
High Availability or Availability usually goes hand-in-hand with Horizontal Scaling. Horizontal Scaling means running the application in at least 2 availability zones . For example, if you have an application hosted on a VM or any other compute service, we want that it should always remain up and running even if underlying server hardware fails.
In this article, we will talk about what scalability and elasticity are and how to treat the symptoms. In system design, there are two single words are confusing, which are scalability and elasticity. There should not a need for manual action if a system is a true cloud. The response system should be completely computerized to respond to changing demands. Businesses are investing heavily in cloud computing resources, and professionals with the right set of skills are much in demand.
Common use cases where cloud elasticity works well include e-commerce and retail, SaaS, mobile, DevOps, and other environments that have ever changing demands on infrastructure services. The purpose of Elasticity is to match the resources allocated with actual amount of resources needed at any given point in time. Scalability handles the changing needs of an application within the confines of the infrastructure via statically adding or removing resources to meet applications demands if needed. In most cases, this is handled by adding resources to existing instances—called scaling up or vertical scaling—and/or adding more copies of existing instances—called scaling out or horizontal scaling.
Users sometimes access websites more often at certain times of the day. Because of elasticity, a company no longer has to maintain support for peak use at all times. Companies can improve user experience by increasing resources at peak usage, and reduce costs by reducing resources when they are no longer needed. Cloud scalability only adapts to the workload increase through the incremental provision of resources without impacting the system’s overall performance. This is built in as part of the infrastructure design instead of makeshift resource allocation .
This includes hardware, software, QoS and other policies, connectivity and other resources that are used in elastic applications. This may become a negative trait where performance of certain applications must be guaranteed. On the flip side, you can also add multiple servers to a single server and scale out to enhance server performance Scalability vs Elasticity and meet the growing demand. With cloud scalability, businesses can avoid the upfront costs of purchasing expensive equipment that could become outdated in a few years. Through cloud providers, they pay for only what they use and minimize waste. The cost savings can really add up for large enterprises running huge loads on servers.
When the resources are much more than required, they are made to scale out until the demand arises again. There are many aspects of cloud computing that CIOs, cloud engineers and IT managers should consider when deciding to add cloud services to their infrastructure. Cost, security, performance, availability and reliability are some common key areas to evaluate.
Ability to restore cloud services in wake of catastrophic loss(natural or human-induced disasters). On the other hand, it takes days or weeks when we submit a request to purchase a physical server, and by when it gets delivered & time is also required to physically set up the server. Scalability is meeting predictable traffic demand while elasticity is meeting sudden traffic demand. As another example, you can configure your system to increase the total disk space of your backend cluster by an order of 2 if more than 80% of the total storage currently available to it is used. If for whatever reason, at a later point, data is deleted from the storage and, say, the total used storage goes below 20%, you can decrease the total available disk space to its original value.
If every 1,000 users you get, you need 2x the amount of servers, then it can be said your design does not scale, as you would quickly run out of money as your user count grew. Simply put, elasticity adapts to both the increase and decrease in workload by provisioning and de-provisioning resources in an autonomous capacity. But autoscaling is not a long-term solution, and additional analysis, design and implementation costs are required to fundamentally solve the scalability issue. It is totally different from what you have read above in Cloud Elasticity.
Environments that do not experience sudden or cyclical changes in demand may not benefit from the cost savings elastic services offer. Use of “Elastic Services” generally implies all resources in the infrastructure be elastic. This includes but not limited to hardware, software, QoS and other policies, connectivity, and other resources that are https://globalcloudteam.com/ used in elastic applications. This may become a negative trait where performance of certain applications must have guaranteed performance. The Elasticity refers to the ability of a cloud to automatically expand or compress the infrastructural resources on a sudden-up and down in the requirement so that the workload can be managed efficiently.
The increase / decrease happens on the fly without physical service interruption. First, bottlenecks must be identified, then the root causes must be figured out, and finally different solutions must be proposed for each bottleneck. This requires an extra investment of time and human resources to enable the system evolution, and autoscaling is a compromise to buy time. By spending additional money, the system is given time to evolve and is not shut down by the inability to scale. Elasticity refers to the capability of a cloud to automatically boost or shorten the infrastructural resources, depending on the requirement so that the workload can be handled efficiently.
These volatile ebbs and flows of workload require flexible resource management to handle the operation consistently. The purpose of elasticity is to match the resources allocated with the actual amount of resources needed at any given point in time. In other words, autoscaling only allows the system to continue to grow with its original scalability, but does not make it better. Both of these terms are essential aspects of cloud computing systems, but the functionality of both the words are not the same.
In elastic systems, resources are neither idle nor missing; instead, they are available. Elasticity goes hand-in-hand with rapid response to dynamic environments. In this type of scalability, virtual machines are spun up as needed to create new nodes that run containerized microservices.
Scalability and elasticity are the most misunderstood concepts in cloud computing. When resource usage does not rise linearly, but exponentially, something is wrong. It could be a bottleneck in usage that results in additional overhead, or a dramatic drop in performance when the amount of data exceeds a certain amount. It is a mixture of both Horizontal and Vertical scalability where the resources are added both vertically and horizontally.
Cloud service providers typically offer a service level agreement that guarantees HA or uptime of resources and services as a percentage. Cloud scalability is not hampered by a company’s physical hardware resources. Whereas the physical nature of hardware made scaling a slower process, in the cloud, scalability is much more efficient and effective.
In the case of needing more processing power, a company moves from a smaller resource to a larger one that is more performant, such as moving from a virtual server with two cores to one that has three. While cloud scaling is automated and fast, often on the order of seconds for new containersand up to minutes for VMs, to bring up new hardware can take some time. Elasticity is the ability to automatically or dynamically increase or decrease the resources as needed. Elastic resources match the current needs and resources are added or removed automatically to meet future demands when it is needed. ELASTICITY – ability of the hardware layer below to increase or shrink the amount of the physical resources offered by that hardware layer to the software layer above. The increase / decrease is triggered by business rules defined in advance (usually related to application’s demands).
Cloud scalability, on the other hand, manages the needs that keep on changing with time. This is done by adding or deleting the resources to ensure that resources are neither lacking nor available in excess. In horizontal scaling, companies add more of an equivalent function, to apportion the workload across multiple servers, keeping performance high and increasing available storage. New employees need more resources to handle an increasing number of customer requests gradually, and new features are introduced to the system (like sentiment analysis, embedded analytics, etc.). In this case, cloud scalability is used to keep the system’s resources as consistent and efficient as possible over an extended time and growth. Use of “elastic services” generally requires that all resources in the infrastructure be elastic.
This is because vertical scaling typically requires a redeployment of an instance or powering down of the instance to make the change, depending on the underlying operating system. Either way, the benefit of doing this in Azure is that we don’t have to purchase the hardware up front, rack it, configure it etc. Rather via clicking in the Azure portal or using code, we can adjust for it.
On the one hand, where elasticity works well in public cloud environments, stability has been known to work the best in private cloud environments. Most of the time, they are confused amongst each other once the concept is taken into consideration. The example would also let you understand the concept of scalability vs Elasticity clearly. As mentioned earlier, Cloud elasticity works the best in a dynamic work environment like those businesses with seasonal offerings for the clients.