Comment 8 for bug 1371757

> IMO log rotation should be based on the size of available disk.
+1 on this.

Folks, considering that we are two days before a release, I suggest a simplest notification mechanism for 6.0, and address this issue better in 6.0.1.
Why can not we just run cron job every X hours, check for a disk space, and do REST API call to Nailgun to /notifications, creating notification there? Then we won't need to bring monit, other complications for now. If this REST API call is complicated for any reason, why not simply run python app then, which would import required nailgun module, and do notification.create - which would create a record directly in DB?
These would be hacks; but in general, I do not think that core nailgun should be also a monitoring service for master node. Let's use other services for it. We might want to use nailgun only as UI notification service. Please note, that it doesn't solve the issue as I probably don't go to UI any often, but at least something for now...