When using mongodb directly on XFS filesystem it automatically shuts down when the XFS defragmentation tool 'xfs_fsr' runs.

This creates a .fsr directory on the mounted filesystem, which causes MongoDB to exit.

The essence of this problem is the same for all other dot directories inside the mongodb map.

One can discuss in length about if it's "proper" to do it this or the other way. But in the end we all know that directories like "lost+found", ".fsr" and really any dot directory in the root of the filesystem can exist and have nothing to do with MongoDB. (Also consider .snapshots etc)

So it makes much more sense it MongoDB would ignore it.

A user tunable parameter that allows to exclude additional file paths would be helpful as well.

This should be a easy-picking patch for people known with MongoDB and very safe to implement. Very little overhead and high usefulness factor.