High server load but not high CPU load

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novazion
Posts: 19
Joined: Mon Mar 08, 2010 10:30 am

High server load but not high CPU load

Post by novazion »

Hello,

I try to identify the reason of my server high load.
I run zoneminder on a 64 BIT Ubuntu Server.
The processor is Core2duo.

I use MRTG-sys to monitor the server.
My server load recording 2 VGA network cams and two megapixels CAMS is around 1.6 average (modect). However, the porcessor load is something around 90%, as it is a dual-core, the processor is not overloaded.

The only thing I see is a high context switches. Something around 2500/s.

Did someone had similar issues?

Emeric.
DREMA
Posts: 162
Joined: Fri Dec 12, 2008 2:39 am
Location: México

Post by DREMA »

Did you check your harddrive activity?

I currently have a bug on my zm that keep overloading my drives and have a very high load even when my processor is fine.

Try installing "iotop" for checking it out.
BlueH2O
Posts: 55
Joined: Thu Aug 12, 2010 10:33 pm

Post by BlueH2O »

If you have a dual core CPU your load average at 100% would be 2.00. So a load of 1.60 would be 80%
Flash_
Posts: 441
Joined: Wed Jan 11, 2006 12:19 pm

Post by Flash_ »

htop can be set to show iowait in the cpu taskbar, and munin will log it effectively too.

For cases as you describe, with high load and normal cpu, then the cpu is usually waiting for io to catch up.
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