> the default settings are liable to lead to data loss In Mongo's defense, the defaults are similar to what you would likely have with a replicated MySQL/Postg

> the default settings are liable to lead to data loss In Mongo's defense, the defaults are similar to what you would likely have with a replicated MySQL/Postgres cluster (single node accepting writes with slaves replicating from there; no concept of write concern). My assumption here is that he is assuming the primary dies before the writes have replicated to the secondaries; that is exactly how master-slave fails too. Maybe there are systems folks can use for having write concern in those databases, but in the companies I've worked for we didn't have them and we definitely didn't have automated failovers