Few months ago I was playing with different VPS providers and I was also considering deploying the application to some “small instance” cloud. I came to Micro Instance of Amazon EC2. Part of the solution I was doing research for is Firebird database and because the pricing looks good, I tried to install Firebird (2.5 SuperClassic) on this instance.
The good news is, that it’s possible. As I did manual install, it was fast. The bad news is, that it’s really slow. If you read the description of Micro Instance you can expect it will not be blazing fast. But even for really low-load database server it’s almost unusable.
I’m not saying you can’t use it. Maybe some slow/late backup/mirror or something like that should be doable. But for normal applications using database server you’ll do better job with your own server or VPS.