On Wed, Oct 25, 2023 at 11:57:54AM +0200, Mike Fischer wrote: > I have been observing occasional bouts of high load averages on several > servers I administer and I am trying to find the cause. (I monitor these > machines so that I can implement corrective measures in case of any > malicious or abnormal activity. I think this is benign, but I’d still > like to find the cause.) > > Once the high load average starts, only a reboot seems to (temporarily) > return the values to their normal levels. > > The actual CPU usage (as measured by vmstat) stays low even if the load > average is elevated. > > The servers are VMs running on a VMWare host (ESXi). This was seen with > OpenBSD 7.3 and 7.4 amd64. > > I can not determine anything inside the VM that causes this. There seems > to be no correlation to pfstat(8) graphs, log entries, known events, or > anything else I can determine. restarting all of the rc.d services never > made any difference. > > Could this be caused by something on the VMWare host machine? (The host > seems to be operating at limit regarding RAM for example. But the VM is > only using the normal percentage of its allocated RAM — way below 100% > and very constant usage, no swap.) > > How can I further debug this, keeping in mind that these are production > machines and experimentation is limited to benign things that don’t > cause outages. >
What is high? A high CPU load for me is in the order of 70+. Please remember the CPU load avarage is a horrible leftover from tenex days. The system just counts how many processes are runnable but it is a very bad indicator of actual CPU load. -- :wq Claudio
