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Spike in CPU Usuage

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I have turned off VM and Docker. For some reason there is a spike in CPU usage every few seconds. Only time it stops is when I stop the arrow. 

 

Also, I have just upgraded from 6.12 to 7.0.1 and my cache drives are 1 array drive is in ZFS. 

 

Do I still need ZFS Master with 7.0.1?

 

 

vault001-diagnostics-20250430-1610.zip

  • Community Expert

zfs master is recommend for additional data yes. Required no...

 

Quote

Only time it stops is when I stop the arrow. 

is that the name of a docker? a VM?

 

this sounds like the cpu still in clock mode giving resources to a VM/Docker.

Spikes are normal when dockers and VM are launched and stopped as resource become available and reused else where...

will review the diag soon. thank you for that to further check and trouble shoot.

  • Community Expert

I'm not seeing anything unusal...

Reviewing the syslogs..

Key Finding

 

here is a recurring pattern where emhttpd and the dynamix plugin are actively applying configurations and restarting subsystems (e.g., Samba, Avahi, Docker, libvirt), especially around Apr 30 16:06:05 onward:

Quote

Apr 30 16:06:05 Vault001 ool www[591895]: /usr/local/emhttp/plugins/dynamix/scripts/emcmd 'cmdStatus=Apply'
Apr 30 16:06:06 Vault001 emhttpd: Starting services...
Apr 30 16:06:06 Vault001 emhttpd: shcmd (143): /etc/rc.d/rc.samba reload
Apr 30 16:06:06 Vault001 emhttpd: shcmd (147): /etc/rc.d/rc.avahidaemon reload
...
Apr 30 16:06:24 Vault001 emhttpd: shcmd (166): /etc/rc.d/rc.libvirt stop
...
Apr 30 16:06:29 Vault001 kernel: BTRFS info (device loop3): last unmount of filesystem
 

??? Array stopped or network disconnected???
 

When this happens, this is/are known to cause temporary spikes in CPU as services reload or containers stop.
...

 


?“Arrow” Reference

When you mentioned "the spike only stops when I stop the arrow", that likely refers to file activity monitoring, particularly file.activity plugin, which is logging:

Quote

Apr 30 16:10:11 Vault001 ool www[609970]: /usr/local/emhttp/plugins/file.activity/scripts/rc.file.activity 'clear'
 

This indicates frequent updates to tracked file activity, which can trigger CPU spikes, especially if it's scanning across many drives or shares.

 

a plugin that is constantly indexing and scanning files could be causing these spikes...

 

Some Test Suggestions:

Temporarily disable the File Activity plugin and see if the CPU spikes stop. (Uninstall it)

Check the Dynamix settings — if there are automatic re-apply settings or periodic triggers (like SMART, temperature, or UPS polling), disable or spread them out.

Run top or htop in Unraid console to watch for which process spikes when the "arrow" is active and not.

 

  • Author

Sorry, I meant to say Array not "Arrow" lol. Will try these suggestions when I get home. Thanks!

  • Community Expert

For the CPU spikes, try uninstalling the cache dirs plugin.

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