mongoDB 禁用大記憶體頁面 transparent_hugepage=never

mongo warning:

2016-09-05T10:55:13.241+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2016-09-05T10:55:13.241+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-09-05T10:55:13.241+0800 I CONTROL  [initandlisten] 
2016-09-05T10:55:13.241+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-09-05T10:55:13.241+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'

如果在運行時解決這問題，也不困難，只需要修改hugepage的設定就可以了。執行下面兩條命令
echo never >> /sys/kernel/mm/transparent_hugepage/enabled
echo never >> /sys/kernel/mm/transparent_hugepage/defrag
別忘了重啟你的mongoDB，這條warning就消失了。不過下次重新啟動系統，這些設定就會消失。