Huge Mongo datasets. How much RAM do I need and how to not get ruined by paying for hosting?

So, I have a what I call huge mongo database which is about 30Gb (about 30 millions documents). I tried to run mongod on the server shared with another application and it was completely slowed down. So I have to look for a dedicated server but have no idea how much RAM do I need.

I understand that I probably need to hav开发者_如何学Goe amount of RAM enough to put all indexes there. But, if I'm correct, it would be about 13Gb of RAM which makes the price for the server very-very expensive (my app isn't making any money yet).

I tried to look into mongoHQ, but their cheapest dedicated plan is $600/month.

Any ideas? Is it really that expensive to host heavy mongo databases like that?

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Build your own server and colocate it instead of renting someone's server. You have full control over the hardware, higher startup costs, but lower long-term costs. You are also liable for hardware malfunctions, so watch out for that.