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agentile
Joined: 01 Apr 2011
Posts: 2
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| Posted: Fri Apr 01, 2011 12:16 pm Post subject: High CPU usage and outbound traffic |
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I have recently experienced high cpu + high outbound traffic (both at the same time) spikes. The process causing the high cpu usage is apache. I started looking through apache logs to see if I could spot anything weird. I didn't notice anything in particular.
Any thoughts to what might be causing this? Possible DOS? Someone simply using a download accelerator app? Is it possible for me to limit the outbound traffic/cpu usage per apache thread? I'm not much of an SA but would like some tips as to how I might be to figure out the root cause of these high cpu and outbound traffic spikes.
I have been using tools like htop, iptraf, tcpdump, etc. I guess I'm just hoping for some assistance from people who may have experienced similar issues and how they went about diagnostics and prevention. Thank you. |
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Guspaz
Joined: 26 May 2009
Posts: 1147
Location: Montreal, QC
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| Posted: Fri Apr 01, 2011 1:19 pm Post subject: |
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| You haven't really provided any details... How much CPU usage? How much traffic? Do your apache logs show particular scripts being accessed at the time of the spikes? etc. |
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agentile
Joined: 01 Apr 2011
Posts: 2
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| Posted: Fri Apr 01, 2011 2:02 pm Post subject: |
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when the spike happens it is usually hovering at 200%, but in one case it went up to 325% . The outbound traffic goes up to about 35Mbits/sec , the time that cpu usage went to 325% outbound traffic went up to 45Mbits/sec . My normal conditions are very low, cpu usage usually in the 0-1% and outbound traffic usually on the lower end of < 1Mbit/sec
I run quite a few vhosts from this machine, and there is quite a bit of log data (each vhost has its own log files). So I admit I'm having some difficulty determining a good way to sift through the legit requests vs something that may be the offending culprit. |
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