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On a small SSD VPS I got 2 GB of RAM and 2 vCPU core (dedicated to my server), virtualized via KVM. So far so good. The server is mainly used for databases (MySQL) and fast network file storage (via sshfs). Currently around 5 folders are mounted to a remote server via sshfs.

When I look into htop I can see 100% CPU load even though when sorting processes by CPU usage none of the processes take up that much CPU on it's own or multiple processes combined. Also the load average indicates that the server is mainly dozing around. From this question I found out that the blue CPU bar indicate that a "Low priority thread" takes up the CPU.

Here are some screenshots: System load via htop System load via top CPU usage from Munin

How can I find out which process is using up all CPU power? Is it even using CPU power or is that just a visual bug, caused by KVM? Does sshfs use cpu power that cannot be tracked from userspace?

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Flatron
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When you're not using your CPUs, they're given to other VMs. This is reflected in the "steal" value that's where most of the usage is. You may want to check with your provider to make sure that you do actually have priority on your two vCPUs. Or just run two CPU eating tasks (like openssl speed) and make sure you get them all.

David Schwartz
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According to the graph you have high steal cpu time, which can cause this. Please, report this problem to your hosting provider and ask him about migrating VM to another host.

The problem generally is that KVM doesn˙t get CPU time from the host possibly due to high concurrency of VMs.

I suppose this will fix your problem with high cpu usage as well.

Yarik Dot
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    There's no problem that needs to be fixed. He's not using his CPUs, so they're being given to someone else. Why is that a problem? – David Schwartz Nov 23 '15 at 11:52