Choosing between single- and multi-tenant comes down to a choice of on-premises vs. cloud. There is no single-tenant version of Salesforce and, in contrast, databases like Oracle are single-tenant so as to have full access to resources.
Security of data is clearly a concern, but that falls primarily on the shoulders of SaaS providers. They are the ones responsible for monitoring tenants and making sure there is no data bleed from one customer to another, and they do a good job of it.
The client’s primary responsibility for securing the data falls to the client's device. All of the major SaaS providers do offer two-factor authentication to secure logins. After that, it’s up to you to maintain the security of the endpoint device.
A major concern between single- and multi-tenant systems is data ownership. Larry Ellison once called Salesforce a “roach motel of clouds,” meaning data goes in but doesn’t come out. Obviously, he was overstating the matter. It is certainly possible to get your CRM data out of Salesforce, but more likely in a CSV format than a SQL database.
Multi-tenancy is at the heart of cloud computing. It is designed to help scale up thousands of users both within an enterprise and externally as companies interact and do business. Whether it’s your Salesforce account or an app you built on AWS for customers, multitenancy can scale through public and private clouds and provide true economies of scale.
Multi-tenancy using cloud data stores
Cloud storage has both financial and security advantages. Financial advantages in the case that the virtual resources are cheaper than dedicated physical resources connected to a personal computer or network.
There are four main types of cloud storage:
Personal Cloud Storage:
It is also called mobile cloud storage which is a subset of public cloud storage that applies to storing an individual's data in the cloud and provides access to data from anywhere. . Apple's iCloud is an example of personal cloud storage.
Public Cloud Storage:
Public cloud storage is where the storage service providers and enterprises are separate and there aren't any cloud resources stored in the enterprise's data center. The enterprise data management is done by a cloud storage provider.
Private Cloud Storage:
A form of cloud storage where the data storage is done within the enterprise. This helps to resolve the potential risk for performance and security concerns while still providing the advantages of cloud storage.
Hybrid Cloud Storage:
Hybrid cloud storage is a combination of private and public cloud storage where some data that is critical resides in the enterprise's private cloud while other data is stored and accessible from a public storage provider.