[harryh]

> have users of foursquare run into problems?

Of course we've run into problems from time to time. No one goes from nothing to foursquare's level of success without running into some bumps along the way.

> were they serious? did someone lose money?

No.

> it would answer whether to use an eventually consistent db

MongoDB actually isn't really an eventually consistent datastore. It doesn't (for example) allow writes to multiple nodes across a network partition and then have a mechanism for resolving conflicts.

[willvarfar]

http://blog.foursquare.com/2010/10/05/so-that-was-a-bummer/

You had 11 hours downtime and didn't lose money?

What about opportunity cost? Reputation?

Now you have to share your secret :)

(I guess, if you weren't profitable, you had nothing to lose?)

[harryh]

The 11 hours of downtime was a pretty big deal, but it had very little to do with MongoDB. It was basically a huge failure in proper monitoring.

[9oliYQjP]

Kudos for not blaming the tool when that would have been the easiest route. It's worth mentioning that 10gen has MongoDB Monitoring Service out now. It makes monitoring MongoDB instances a lot more accessible and convenient.

[willvarfar]

That's not how everyone remembered it at the time, nor the picture the blog painted. And the mongo monitoring thing is much newer, right? Its like saying that a fire wasn't a big deal because next time there'll be a fire station.

Stockholm syndrome?

Or perhaps investor pressure to close ranks ;)

[jm3]

If you don't have paying customers (Foursquare), you're not going to lose much in hard dollars when your service falls over. Reputation points? Sure. Dollars, not so much.

[maxmcd]

Drawing a line between the difference in losing money for a paying service and a free service, while technically correct, is not the best business practice. Any online business looses money by being down, whether they can easily quantify it or not.

[gsharm]

Where do you finally persist the data in that case?