Comment 0 for bug 1413702

Currently we leave sysctl vm.swappiness parameter value as is - 60% by default.

For controllers and nodes running databases (Mongo, Zabbix) default value is incorrect.
Recommended is sysctl vm.swappiness=10
It prevents swapping when about 60% of RAM is free.

Additionally, this parameter may be reduces for all the other nodes as well.
We do not use and do not recommend load, which may result in swapping. And we better avoid swapping as much as possible.

For high performance multiple CPU socket systems setting this parameter to 5-10 is even more important, since the amount of free RAM and swapping is going based not on total RAM available but on per-socket plugged in RAM amount (per NUMA node RAM size).

Symptoms are unexpected RabbitMQ or MySQL slowdowns, broken and timed-out connections on the very high end systems with a lot of free resources..