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?

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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 ;)