Running MongoDB 2.4.11 on Ubuntu 14.04.1 LTS

In top, this mongod thread is constantly using ~195% CPU:

24524 mongodb   20   0 4676092 767556 719184 S 194.9 37.4 221:15.16 mongod

When I strace the PID, I get endless:

select(11, [9 10], NULL, NULL, {0, 10000}) = 0 (Timeout)

Which I believe is a problem with Mongo Timeout? But I'm not totally sure, as I'm new to server problem solving.

MongoDB config: http://pastebin.com/sheb1hTG

Tail from from Mongo log: http://pastebin.com/V5apSsq5

Sample from mongostat: http://pastebin.com/VRQzqn3D

I have 7 Node.js servers connected to Mongo running on this Ubuntu – I know it's excessive, but only 2 servers are causing the CPU overload issue – when I turn them both off, the the CPU% returns to normal.

I'm not sure what to be looking for with how these Node servers are implemented and how it might be causing the Mongo issues.


I had a similar problem with clean install of MongoDB onto RHEL 6.3 using the supplied repos

mongodb-org.x86_64                               3.2.0-1.el6

post install, service started up with no errors, but CPU was over 100%. I also noticed extremely high soft irq and millions of context switches. In my case, something was wrong with the virtual machine, and following a reboot, the problem was solved. It seems that the strace output above is "normal" for MongoDB - some kind of polling it uses?

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