Yes, using Microsoft SQL Server for Linux; hosted both on-premises with VMware and in Azure Virtual Machines - later migrated to Azure SQL Managed Instances. It worked great for the business’ needs. The major architectural advantage was that each Customer had a completely isolated Tablespace, easing compliance auditing. Each DB could be exported/migrated to a different Instance or Region, and migration scripts running slow for “whale” customers had no effect upon small fish. Monitoring of the Servers and individual Instances was straightforward, albeit very verbose due to the eventual Scale.There were a few administrative drawbacks; largely because the MS-SQL Server Management Studio tools do not scale well to hundreds of active connections from a single workstation, worked-around through lots of Azure Functions runs instead. Costs and instance sizing were a constant struggle; though other engines like Postgres or even SQLite would likely be more efficient.
I have also seen this used in other formats quite successfully - Fandom/Wikia (used to?) use a MySQL database for each sub-site.
BrentOzar|2 months ago
Stack Overflow used it as well, with a database per site (DBA.StackExchange.com, ServerFault, SuperUser, Ask Ubuntu, etc.)
I have a bunch of clients using it. Another drawback with this design is high availability and disaster recovery can become more complex if you have to account for an ever-growing number of databases.