Companies that need scalability calculate the increased resources they need, and plan for peak demand by adding to existing infrastructure with those resources.
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.
Cloud scaling allows for automation, which helps quickly scale systems to meet demand. Cloud scaling is generally performed in private cloud environments. For the most part, cloud scaling is either scaling up or scaling out.
Scaling up is also known as vertical scaling.
When scaling up, resources are added to an existing cloud server. This can include CPU processing power, memory, and storage and is often limited to the resources available in existing hardware.
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 containers and up to minutes for VMs, to bring up new hardware can take some time.
Scaling out is also known as scaling horizontally. This is used by companies that need high availability and little or no downtime with applications.
In horizontal scaling, companies add more of an equivalent function, to apportion the workload across multiple servers, keeping performance high and increasing available storage.
Containerized applications are a good fit for scaling out. In this type of scalability, virtual machines are spun up as needed to create new nodes that run containerized microservices. Think of it as adding the same type of services already running to spread out the workload and maintain high performance.
With scale, it’s possible to overprovision and pay for computing resources that are not necessary and stand idle. It’s also possible to underprovision and suffer outages from having too little capacity for the workload. For these reasons, and others, elastic cloud systems are the right fit for some companies.