We upgraded the Mono/.NET framework in Toolforge/GridEngine from the 3.x version to 5.x [0]. We discovered that some tweaking is required due to some weird behavior regarding memory allocation by the framework [1]. The first symptom you will see is your boot doing high CPU load (spins). The fix is easy, just telling Mono that more memory is available when running the tool/bot. But you require to cancel your job submissions and resend. Please refer to the phabricator bug [1] for more details. Sorry for the inconvenience. [0] https://phabricator.wikimedia.org/T194665 [1] https://phabricator.wikimedia.org/T195834