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On-prem vs cloud storage: Can cloud ever be as secure?

image of a server room
(Image credit: Photo by Manuel Geissinger from Pexels)

In today’s data-centric business environment, having data security infrastructure that you can trust is absolutely essential. As cyberattacks become more frequent and more sophisticated, the need to bolster security only grows by the day.

At the same time, many companies are considering transitioning from on-premises (on-prem) computing infrastructure to cloud infrastructure for the first time. The price of cloud computing has dropped precipitously in recent years, and it offers advantages in terms of scalability and data integration. 

But can the best cloud storage platforms ever match the level of security afforded by storing data on-premises? In this article, we’ll cover everything you need to know about on-prem vs cloud storage, specifically focusing on data security.

What is on-prem storage?

woman on laptop next to data center

On-prem storage means the servers are located in your offices (Image credit: Unsplash)

On-prem storage involves keeping all of your servers and data in your offices, typically in a single location. On-prem storage is commonly used because your data is readily available to be restored in the aftermath of a network failure or attack.

With on-prem storage, it’s up to your company’s IT team to manage and maintain your computing infrastructure. The advantage of this is that since you’re in control of your own storage resources, your system is fully customizable to meet your company’s changing IT needs.

What is cloud storage?

With cloud storage, your data is stored off-site on servers owned by a third-party firm. The servers containing your data are typically warehoused in data centers that can be anywhere in the world.

Your IT team doesn’t have control over the physical computing infrastructure on which your data is stored, but you typically still have tight control over how data is managed and accessed. The cloud storage company you contract with is responsible for maintaining the physical servers and expanding capacity as needed.

On-prem vs cloud storage: Durability and availability

server rack on fire

Data durability is integral to choosing between on-prem and cloud storage (Image credit: Shutterstock)

Among the main concerns that companies have when it comes to storing data in the cloud are data durability and availability. Durability describes the probability that your data is protected against events like server failures. Availability is a measure of whether you can access your data on demand.

In both of these respects, cloud storage beats on-prem storage. Most enterprise-scale cloud storage providers store copies of your data redundantly, in multiple independent data centers distributed across the US or even in multiple countries. If one data center fails from a fire or earthquake, for example, your data is still safe and accessible in another data center.

On top of that, many cloud storage services run frequent, automatic data integrity checks to ensure that all of these redundant backups are operational. Amazon Web Services (AWS) offers 99.999999999% durability, meaning that the probability of losing your data in any given year is just one in 100 billion. AWS also promises that your data is available on-demand 99.99% of the time in any given year.

It’s virtually impossible to match these figures with on-prem data storage. Most companies with on-prem storage have just two servers, one of which serves as a backup in the event of a network outage or server failure. However, this system isn’t robust against larger-scale events, like natural disasters, that could take out both on-prem servers.

Physical and technical monitoring

Data security means more than simply protecting against data loss. It also means protecting against data theft. From that perspective, it takes more than simply keeping redundant copies of your data to keep your information safe.

To start, it’s essential that your physical servers are safeguarded from physical theft. While files on your servers are typically encrypted at rest for both on-prem and cloud storage, it could still be a catastrophe if an entire server’s worth of data falls into someone else’s hands.

Cloud storage data centers are more attractive targets for potential thieves than the server rooms of individual businesses. However, data centers also benefit from an economy of scale: cloud storage providers can afford to pay for 24/7 security teams, electronic access controls, locked server cages, and other physical security features.

Implementing these same controls for on-prem servers is possible, but costly. Even with advanced security measures in place, it can be difficult for individual businesses to protect against the threat posed by disgruntled employees.

Digital security is also critical to safeguard your data from computerized attacks. Cloud storage companies can easily afford 24/7 cybersecurity teams to monitor for threats and proactively protect infrastructure. They also have full-time teams dedicated to keeping software and servers patched with the latest security updates. Very few businesses can afford to mimic these digital security operations in-house.

User access management

an office full of workers at computers

Managing user access is a key facet of data security (Image credit: Shutterstock)

Managing which users can access what data is another important component of data security. Once again, cloud storage has an edge over on-prem storage.

Enterprise-scale cloud storage infrastructure was built with an eye towards user access management. IT managers have the administrative controls needed to impose fine-grained controls on data access and sharing, as well as the ability to track files that are shared outside of your company’s network.

Importantly, cloud storage infrastructure can also be secured with multi-factor authentication, time-restricted access, and other advanced tools, all of which can be configured with just a few clicks.

These administrative and access controls are also available for on-prem storage. However, it’s time-consuming and costly to implement them within a custom network infrastructure. In some cases, your IT administrators may need to build a user access management system from scratch.

Encryption

One area in which on-prem storage has a slight security edge over cloud storage is encryption. With on-prem storage, your IT team can use a physical device known as a hardware security module to store your data encryption keys behind a firewall. 

That’s an ultra-secure way to ensure that even if your servers are breached by a hack, the thieves can’t gain access to the administrative side of your network or de-encrypt any stolen files. In fact, this is so secure that many cloud storage services now offer on-prem storage at your business for your encryption keys. 

Your encryption keys are stored inside your organization’s offices and behind a firewall, then used to encrypt data before it’s sent to the cloud. Your cloud storage provider never has a copy of your encryption keys, so any data that might be stolen during transfer to the cloud can’t be de-encrypted. 

By relying on on-prem storage for this one specific aspect of your network configuration, cloud storage can be just as secure as on-prem storage.

Is cloud storage secure?

user at laptop with security icons overlaid

Data stored in the cloud provides security against loss and theft (Image credit: Song_about_summer/Shutterstock)

Cloud storage has moved beyond simply trying to keep up with on-prem storage when it comes to data security. In many ways, data stored in the cloud is more secure against data loss and theft than data stored locally on your own servers. In more detail, you can learn why cloud storage is secure, which includes tips on how to use it securely.

It’s certainly possible for on-prem data security to meet or even exceed the security standards of the cloud. But for most businesses, implementing the necessary security measures on-premises is so costly as to be virtually impossible. Unless your business has multiple offices, a 24/7 security team, and an unlimited IT budget, cloud storage is more secure than on-prem storage.

If you want to learn more about the security of cloud storage, read our feature asking how secure is cloud storage, which also discusses the most secure providers; and take a look at what you should look for in a secure cloud system.

Michael Graw is a freelance journalist and photographer based in Bellingham, Washington. His interests span a wide range from business technology to finance to creative media, with a focus on new technology and emerging trends. Michael's work has been published in TechRadar, Tom's Guide, Business Insider, Fast Company, Salon, and Harvard Business Review.