Vertical vs Horizontal Scaling

Vertical vs Horizontal Scaling

We all want growth, but we often find ourselves unequipped to deal with it. It’s a bit like going to the gym, lifting weights, and seeing real results, only to realize that we no longer fit into our old clothes. Now we have to decide if we want to modify them or buy new clothes.

What Is Scalability?

Scalability describes a system’s elasticity. While we often use it to refer to a system’s ability to grow, it is not exclusive to this definition. We can scale down, scale up, and scale out accordingly.

If we are running a website, web service, or application, its success hinges on the amount of network traffic it receives. It is common to underestimate just how much traffic our system will incur, especially in the early stages. This could result in a crashed server and/or a decline in the service quality.

Thus, scalability describes a system’s ability to adapt to change and demand. Good scalability protects us from future downtime and ensures the quality of our service.

But what options do we have when it comes to implementing scaling and ensuring our business’s scalability? That’s where horizontal and vertical scaling come in.

What Is Horizontal Scaling?

Horizontal scaling (aka scaling out) refers to adding additional nodes or machines to our infrastructure to cope with new demands. If we are hosting an application on a server and find that it no longer has the capacity or capabilities to handle traffic, adding a server may be our solution.

It is quite similar to delegating workload among several employees instead of one. However, the downside of this may be the added complexity of your operation. we must decide which machine does what and how our new machines work with our old machines.

What Is Vertical Scaling?

Vertical scaling (aka scaling up) describes adding additional resources to a system so that it meets demand. How is this different from horizontal scaling?

While horizontal scaling refers to adding additional nodes, vertical scaling describes adding more power to our current machines. For instance, if our server requires more processing power, vertical scaling would mean upgrading the CPUs. We can also vertically scale the memory, storage, or network speed.

Additionally, vertical scaling may also describe replacing a server entirely or moving a server’s workload to an upgraded one.

Advantages of horizontal scaling:-

Scaling is easier from a hardware perspective - All horizontal scaling requires us to do is add additional machines to your current pool. It eliminates the need to analyze which system specifications you need to upgrade.

Fewer periods of downtime - Because you’re adding a machine, you don’t have to switch the old machine off while scaling. If done effectively, there may never be a need for downtime and clients are less likely to be impacted.

Increased resilience and fault tolerance - Relying on a single node for all your data and operations puts you at a high risk of losing it all when it fails. Distributing it among several nodes saves you from losing it all.

Increased performance - If you are using horizontal scaling to manage your network traffic, it allows for more endpoints for connections, considering that the load will be delegated among multiple machines.

Disadvantages of horizontal scaling

Increased complexity of maintenance and operation - Multiple servers are harder to maintain than a single server. Additionally, we'll have to add software for load balancing and possibly virtualization. Backing up our machines may also become a little more complex. we'll have to ensure that nodes synchronize and communicate effectively.

Increased Initial costs - Adding new servers is far more expensive than upgrading old ones.

Advantages of vertical scaling

Cost-effective - Upgrading a pre-existing server costs less than purchasing a new one. Additionally, we are less likely to add new backup and virtualization software when scaling vertically. Maintenance costs may potentially remain the same too.

Less complex process communication - When a single node handles all the layers of our services, it will not have to synchronize and communicate with other machines to work. This may result in faster responses.

Less complicated maintenance - Not only is maintenance cheaper but it is less complex because of the number of nodes we will need to manage.

Less need for software changes - We are less likely to change how the software on a server works or how it is implemented.

Disadvantages of vertical scaling

Higher possibility for downtime - Unless we have a backup server that can handle operations and requests, we will need some considerable downtime to upgrade your machine.

Single point of failure - Having all our operations on a single server increases the risk of losing all our data if a hardware or software failure was to occur.

Upgrade limitations - There is a limitation to how much we can upgrade a machine. Every machine has its threshold for RAM, storage, and processing power.