We've hit a scenario where background LCS compactions will stall. compactionstats output shows hundreds of pending compactions but none active. The thread dumps show no CompactionExecutor threads running, and no compaction activity is being logged to system.log. This seems to happen when there are no writes to the node. There are no flushes logged either, and when writes resume, compactions seem to resume as well, but still don't ever get to 0.