[clamav-users] Clamd high CPU during clamdscan

Dennis Peterson dennispe at inetnw.com
Wed Jan 27 01:38:24 EST 2016

The "nice" utility is your very best friend. It yields CPU time to other 
operations but will run like crazy of nothing else is a higher priority. Clam is 
a disk IO heavy process for obvious reasons, and can drive disk waits up quite 
high. It is also CPU intensive but should occupy a single core. There is no way 
around the disk IO problem because it scans files. But - if you run it just 
after a system backup chances are good it will find many of the files it scans 
in cache. That helps reduce disk IO but bumps up CPU load.


On 1/26/16 10:26 AM, Jeff Johnson wrote:
> I have rolled out clamd to a handful of Red Hat systems and they all seem
> to have high CPU usage when clamdscan runs at 2am. The rest of the day,
> clamd drops down to minimal usage. There isn't a lot of change on these
> systems so I can't imagine it's finding much, but it really pegs the CPU's.
> What configuration settings could I change for clamd or clamdscan to not
> hammer the CPU?
> Thanks
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