I just got off a sales call with a prospect who is evaluating MongoDB.

They claim that mongod crashes when it turns out of disk space. They
are using XFS. From their description, it sounds like this is
happening when it tries to preallocate the next file to use and there
isn't enough space. I tried a quick search in Jira, but didn't see
anything obvious. Has anyone seen anything like this before, or is
this a known problem?

Dwight sez: "i think that is correct. we have not done any work on out of disk space really."