Database and DB engine for social website

For a heavy user content website with user profiles, live feeds, photo /video/content sharing, etc what DB to use, and what DB engine? Ofcourse Oracle/Microsoft sql are out because they are not free (or cheap). I am using MySQL with MyISAM but that will run into performance issues on a social site. Even using InnoDB may not help performance. So firstly which DB is better to use and which engine - starting from Free to paid?

Main concern is with live feeds performance, plus there is lots of data tracking and mining with analytic.

Since this is a startup - hardware costs are limited so no hardware farm here to support performance, hence seeking a d开发者_开发知识库ecent alternative for the first 2 years atleast.

If you are a start-up, you may be able to afford Microsoft's stuff after all. Check out their BizSPark program which gives you software for free for a few years.

I am not sure that I agree that MySQL is not your best option though. Doesn't FaceBook use MySQL? Are you expecting to be bigger?

If you think that InnoDB will be too slow for you, there are other storage engine options on MySQL. For example, have you investigated TokuDB?

Have you considered a hosting service like Linode.com instead of your own hardware? This might be a better fit for your cashflow profile. If you really feel the DB load is onerous, you could have dedicated or multiple servers. Start with a dedicated DB box and scale up from there. You could also go with a cloud service like Amazon EC2.

EDIT: I just realized that Tokutek have a social networking case study: http://tokutek.com/customers/a-social-networking-case-study/

It sounds to me like you are unlikely to outgrow MySQL any time soon. If you grow busy enough to need anything like TokuDB you can thank me with a few shares. :-)

If your userbase is large enough to require a high-performance DB, your bandwidth and storage charges will not be cheap; why skimp on the database?

MS SQL has free and/or cheap editions which are performance-inhibited. I always start with them, and if the site takes off, I upgrade. Probably Oracle offers something similar.

Edit: I should have said at the start that you're unlikely to outgrow MySQL anytime soon, and that this whole question might be a case of premature optimization.

I would recommend getting a cloud account for the files and potentially a dedicated server for the DB (MySQL and MyISAM).

You can limit your cost on the cloud storing the files, but enhance performance by having a dedicated server for the DB by increasing processing power and memory.