I was hit by the transparent huge pages on RHEL 6.2 in my workload. If you find our ordinary processes randomly taking up huge amounts of CPU time -- system CPU time -- when doing apparently ordinary tasks, you might be affected too. That was a real pain to diagnose when you're used to trusting the kernel not doing anything that weird. Running "perf top" helped to narrow down what the system was REALLY doing.
I didn't have LI-size databases -- just a dozen Python processes allocating each perhaps 300MB and all restarting at the same time were enough to trigger it, taking 10 minutes rather than 2 seconds to start up.
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I was hit by the transparent huge pages on RHEL 6.2 in my workload. If you find our ordinary processes randomly taking up huge amounts of CPU time -- system CPU time -- when doing apparently ordinary tasks, you might be affected too. That was a real pain to diagnose when you're used to trusting the kernel not doing anything that weird. Running "perf top" helped to narrow down what the system was REALLY doing.
I didn't have LI-size databases -- just a dozen Python processes allocating each perhaps 300MB and all restarting at the same time were enough to trigger it, taking 10 minutes rather than 2 seconds to start up.