Is it fine to run a public high traffic website on a sql server 2008 express db?
Here is a partial list of restrictions of this version:
- Number of CPUs: 1
- Maximum memory utilized: 1 GB
- Maximum database size: 10 GB
- Replication: Subscriber only
- Backup compression: N/A
- Most of performance features is not available.
See comparison list for more details
Depending on your definition of high traffic, it is likely that you will see awful performance. If there is any transactional writes that happen often, you'll cap out the max database size rather quickly, and as mentioned above there are many hardware restrictions on express. Not to mention you don't have all the creature comforts for a professional enterprise instance (SQL Agent, etc.).
SQL Server express is more for embedded applications, or very small low-budget intranet applications.