I'd like to add that RHEL5 was more than tolerable in this aspect. Whatever kernel series it lived through, it seemed logical. We knew when RHEL5 systems start

I'd like to add that RHEL5 was more than tolerable in this aspect. Whatever kernel series it lived through, it seemed logical. We knew when RHEL5 systems started to swap that was our sign to A) look for long term usage growth that is beginning to bump some threshold somewhere B) someone turned a knob they shouldn't have C) a recent code change has caused a problem in the application stack Then RHEL6 came along, and it swapped all the time. Gone was our warning. The stats shows tens of gigabytes of cache engaged. WUT? How do we have tens of gigabytes of memory doing nothing? Before you could finish that thought, OOM killer was killing off programs due to memory pressure. WTF? The system is swallowing RAM to cache I/O, but couldn't spare a drop for programs? ...I could go on, but simply put, RHEL6 was garbage. And really I mean the RHEL6 kernels and the way that Red Hat tweaked whatever they did for it. RHEL7 was a little better, but still seeing echoes of the ugliness of RHEL6. RHEL5 was just a faded pleasant dream. The last 3 Fedoras on the other hand, the memory management seems like we're finally digging ourselves out of the nightmare. That nightmare lasted almost a full decade.... sheesh