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Load average spikes once an hour


 
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# 1  
Load average spikes once an hour

Hi,

I am getting a high load average, around 7, once an hour. It last for about 4 minutes and makes things fairly unusable for this time.

How do I find out what is using this. Looking at top the only thing running at the time is md5sum.

I have looked at the crontab and there is nothing running at this time, so is there a number of hidden crontabs that I don't know about?

Any help would be greatly appreciated.

Running WHM/Cpanel on CentOS

Thanks
Matt
# 2  
There's all the user crontabs of course, also check for filenames under /etc/cron.hourly, these will as the name implies get run hourly. This doesn't rule out some script somewhere that does this of its own volition either, just a "while true ; do sleep 3600 ; hog_system ; done"

Depending on your system your version of ps may be able to print a tree of what created what process (or at least what process belongs to what process), potentially helpful for tracking down what's spawning the monster. Try ps -ejH

I wouldn't expect a high load average to lag the system, Linux is pretty good at keeping responsive despite high CPU load, but if something's hogging disk access -- like many instances of md5sum could -- that'd definitely slow things down by turfing useful things out of cache.
# 3  
excellent, found the problem using the ps command.
This User Gave Thanks to sm9ai For This Post:
# 4  
Same thing on my VPS

I recently signed up for a VPS with CentOS and CPanel/WHM. The exact same thing is happening on mine. Spikes every hour, on the hour. They last about 4 minutes and during that time there is piss poor system performance.

High IO Wait time. Memory levels are fine. No RAM swapping.

I monitored top during these spikes and the process that kept floating to the top was: md5sum

---------- Post updated at 03:42 AM ---------- Previous update was at 03:37 AM ----------

By the way, how do we fix what is going on? I am running "ps -ejH" but not sure what to look for. It is neat looking at the process tree! Sweet command.
# 5  
You may find this useful.

"Top 10 CPU Utilized Processes"
Code:
ssh -Tqn $1 ps auxf | sort -nr -k 3 | head -10

"Top 10 Memory Utilized Processes"
Code:
ssh -Tqn $1 ps auxf | sort -nr -k 4 | head -10

# 6  
lfd / md5sum

ps -ejH
Code:
22019 22019 22019 ?        00:00:03   lfd
26292 22019 22019 ?        00:00:00     lfd
26293 22019 22019 ?        00:00:00       md5sum

ps auxf | sort -nr -k 3 | head -10
Code:
root     26293  0.5  0.0   2928   620 ?        D    05:00   0:00  |   \_ /usr/bin/md5sum --check /etc/csf/cs
f.tempint
root     28483  0.2  1.2  16816 12908 ?        D    05:00   0:00  \_ lfd - checking directories

What is lfd and any ideas how to bring this under control?
# 7  
You may find this helpful.
LFD Process Email Alerts - Web Hosting Talk

---------- Post updated at 04:06 AM ---------- Previous update was at 04:04 AM ----------

Quote:
Originally Posted by Brian294
ps -ejH
Code:
22019 22019 22019 ?        00:00:03   lfd
26292 22019 22019 ?        00:00:00     lfd
26293 22019 22019 ?        00:00:00       md5sum

ps auxf | sort -nr -k 3 | head -10
Code:
root     26293  0.5  0.0   2928   620 ?        D    05:00   0:00  |   \_ /usr/bin/md5sum --check /etc/csf/cs
f.tempint
root     28483  0.2  1.2  16816 12908 ?        D    05:00   0:00  \_ lfd - checking directories

What is lfd and any ideas how to bring this under control?
I can see its not taking your cpu as much as you are worried it is.
It is just 0.2% of your cpu and you shouldn't be worrying about it.
 

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