Many PaaS solutions include support for a database, such as MSSQL or MySQL. Often, these database solutions connect to a cloud-based server, as shown in FIGURE 6-12, and, as such, can be considered a cloud-based database.
A better definition of a cloud-based database, however, is a database that can not only be used by applications that reside (are hosted) in the cloud, but also by applications that reside within the customer’s on-premise data center, as shown in FIGURE 6-13.
Cloud-based database solutions include the following advantages:
Cost-effective database scalability: Cloud-based databases can scale dynamically to meet customer needs on a pay-as-you-go basis.
High availability: Cloud-based database systems normally reside on redundant hardware, which results in high system up time.
High data redundancy: Cloud-based databases are normally replicated behind the scenes to increase data availability.
Reduced administration: The cloud-based database provider maintains the database version updates and patches.
Data compression: Behind the scenes, the cloud-storage solution may compress content to reduce the amount of space, and thus costs, the cloud-based data requires.
Cloud-based databases can also include the following disadvantages:
Data security concerns: Some users still do not feel comfortable storing a database system in the cloud.
Performance: Because data queries may travel the Internet, the cloud-based database access will not be as fast as a local database solution would.