When to shard a database? When to increase Hardware?

I currently have an ASP.net web application running on IIS using an SQL database. The site receives a growing amount of traffic and I want to start thinking about scaling the website up and ensuring I get good performance on the site and the DB.

How do I decide or ascertain when to increase hardware resources (more ram, clustered servers etc) for a SQL database runnin开发者_StackOverflowg a website or shard the database and run the sharded DB's on other servers?

If this does not belong on this site, please point me to the relevant site.

Well, simply said you shard it when growing the hardware makes no sense financially.

That is quite high, though - I would not go sharding before you have somewhere around 72 discs for a server and 2 physical cpu slots ;)

I say 72 discs because SuperMicro fits those into a 4 rack unit high case - which is quit a nice sweetspot ;)

After that, a single box gets EXPENSIVE. This is a lower mid range server from the CPU / RAM so it is quite ok from a price perspective ;)