Question

I am working with an application where we store our client data in separate SQL databases for each client. So far this has worked great, there was even a case where some bad code selected the wrong customer ids from the database and since the only data in the database belonged to that client, the damage was not as bad as it could have been. My concerns are about the number of databases you realistically have on an SQL Server.

Is there any additional overhead for each new database you create? We we eventually hit a wall where we have just to many databases on one server? The SQL Server specs say you can have something like 32000 databases but is that possible, does anyone have a large number of database on one server and what are the problems you encounter.

Thanks,

Frank

Answer 1

The upper limits are

• disk space
• memory
• maintenance

Examples:

• Rebuilding indexes for 32k databases? When?
• If 10% of 32k databases each has a active set of 100MB data in memory at one time, you’re already at 320GB target server memory
• knowing what DB you’re connected too
• …

The effective limit depends on load, usage, database size etc.

Edit: And bandwidth as Wyatt Barnett mentioned.. I forgot about network, the bottleneck everyone forgets about…