[rubyrescue]

I don't consider redis durable for similar reasons as mongo - yet redis doesn't hide what it is or what it lacks in terms of durability... so it doesn't bother me that it isn't.

but mongo often downplays it's lack of durability, which makes me wary of using it or recommending it because people don't know how to use it.

[rbranson]

This is exactly the problem with MongoDB. It's practical use is a semi-durable, in-memory data store, but they advertise it as a data store of record that can be used for large, >RAM sets of any conceivable use case.