Pros and cons of external database services (mongohq, etc.)

For putting together a s开发者_Python百科ite from scratch, what are the advantages and disadvantages of using external database services, e.g. MongoHQ, Amazon RDS?

Advantage: you don't have to fix it yourself when it breaks.
Disadvantage: you can't fix it yourself when it breaks.

My take on this is simple:

If you have an application hosted on Amazon then you should go for Amazon RDS or MongoHQ(which also is hosted on Amazon). The rational is, since both your application and the database are on the same network (internally) you will get a significant performance advantage.

If your application is hosted else-where then go for a local install.

a couple more points

for

• do not have to administer the Hardware
• I guess they take care of security, software updates of the server (Software admin)
• saves room. you do not have to find room in your building for a database cluster

disadvantages

• depending on your internet speed, the speed you transfer data can be affected. if the application and data are in the same network you could say that you have 1gbit speed vs a 50mbit internet connection. times this by 1000 concurrent users?
• you have to work to their release schedule. if you use a 3rd party and they update the database version which has a breaking change. You will be forced you update. if you host it yourself this upgrade will be under your terms.