Periodic power consumption spikes on Proxmox VE 9.1.6 (Dell OptiPlex 7050) – normal behavior?

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andyB2018

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Nov 6, 2024
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Hi everyone,

I’m trying to understand if the power consumption pattern I’m seeing on my Proxmox setup is normal or if it indicates some background activity that I’m missing.

Setup:
  • Proxmox VE: 9.1.6
  • Kernel: Linux 6.17.13-2-pve (2026-03-13)
  • Hardware: Dell OptiPlex 7050
  • CPU: Intel i5-6600T (4 cores, 1 socket)
  • RAM: 16 GB
  • Boot mode: Legacy BIOS
  • Workload: only one VM running (Home Assistant)
Observation:
I’m monitoring total system power consumption and I see a repeating pattern:

  • Periods where consumption is relatively flat and stable (~4–5W baseline with minor noise)
  • Followed by intervals with frequent spikes up to ~20–25W
  • Then it goes back again to a “calm”/flat period
For example, between ~09:30–09:45 the consumption is very stable, then spikes start appearing again, and this pattern repeats over time.

Question:
Is this kind of periodic behavior expected on Proxmox?

I’m particularly interested in:
  • What processes or subsystems could cause these periodic spikes
  • Whether this is typical for a lightly loaded system with a single VM
  • Any tools/commands you’d recommend to correlate power spikes with system activity
CPU governor is set to powersave, and log2ram is active.

Thanks!
 

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Firstly I don't believe this is unusual.

Secondly, you seem to infer this is a PVE/host issue. I believe it is more likely the VM (Home Assistant) activity that is causing this. Home Assistant usage can be very varied (I've used it for years & constantly monitored its' temps & power draw). It gets up to all sorts of tasks & shenanigans depending on your specific setup. Its hard to compare 2 instances of HA apple for apple, since no 2 instances will be alike, but I also notice spikes from time to time, on a daily basis. I created an hourly average sensor to better monitor the situation for CPU temps, & it is pretty stable except when doing any updates/upgrades. You could create one for power draw and monitor that. Also, try looking at HA activity/history/logs for those spike periods.

If you really want to test - shutdown that VM & monitor the pure (hourly/daily?) PVE/host power draw. (Maybe difficult as it appears you are using HA to monitor this, also you may have a blackout without HA up & running!).
 
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Run something like this and check what triggers the elevated load
Bash: 
top -em -co%CPU
If it occurs too infrequently to monitor live like this you need something like netdata.
 
Last edited:
nmateo said:
Hello, can you post your VM(s) or Host proxmox dashboard usage graphs please
Click to expand...
The peaks you see in the graphs at 1 AM and 5 AM are VM backup and then backup inside HA to Google Drive.
gfngfn256 said:
Firstly I don't believe this is unusual.

Secondly, you seem to infer this is a PVE/host issue. I believe it is more likely the VM (Home Assistant) activity that is causing this. Home Assistant usage can be very varied (I've used it for years & constantly monitored its' temps & power draw). It gets up to all sorts of tasks & shenanigans depending on your specific setup. Its hard to compare 2 instances of HA apple for apple, since no 2 instances will be alike, but I also notice spikes from time to time, on a daily basis. I created an hourly average sensor to better monitor the situation for CPU temps, & it is pretty stable except when doing any updates/upgrades. You could create one for power draw and monitor that. Also, try looking at HA activity/history/logs for those spike periods.

If you really want to test - shutdown that VM & monitor the pure (hourly/daily?) PVE/host power draw. (Maybe difficult as it appears you are using HA to monitor this, also you may have a blackout without HA up & running!).
Click to expand...
As far as I remember I did move HA to another PVE and shutdown it on the actual host. The consumption was the same (minus a few 0.5W for HA running).
Impact said:
Run something like this and check what triggers the elevated load
Bash: 
top -em -co%CPU
If it occurs too infrequently to monitor live like this you need something like netdata.
Click to expand...
top - 19:13:36 up 8 days, 2:48, 2 users, load average: 0.40, 0.26, 0.20
Tasks: 195 total, 1 running, 194 sleeping, 0 stopped, 0 zombie
%Cpu(s): 1.4 us, 2.4 sy, 0.0 ni, 96.2 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 15858.3 total, 739.4 free, 5594.0 used, 9916.8 buff/cache
MiB Swap: 8192.0 total, 8190.3 free, 1.7 used. 10264.2 avail Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4712 root 20 0 5025.8m 3.8g 12.3m S 5.6 24.5 15,35 /usr/bin/kvm -id 100 -name haos17.1,debug-threads=on -no-shutdown -chardev socket,id=qmp,path+
722 root 20 0 1387.5m 109.6m 24.5m S 1.3 0.7 38:40.53 /usr/sbin/tailscaled --state=/var/lib/tailscale/tailscaled.state --socket=/run/tailscale/tail+
3071522 www-data 20 0 230.5m 164.4m 13.3m S 0.7 1.0 0:05.17 pveproxy worker
3084789 www-data 20 0 229.1m 159.9m 10.5m S 0.7 1.0 0:03.36 pveproxy worker
3109691 root 20 0 6.9m 3.4m 3.1m S 0.7 0.0 0:00.52 bash -c while true; do sleep 1;head -v -n 8 /proc/meminfo; head -v -n 2 /proc/stat /proc/vers+
782 _chrony 20 0 19.5m 3.6m 2.8m S 0.3 0.0 0:01.32 /usr/sbin/chronyd -F 1
3006239 root 20 0 222.8m 153.1m 8.8m S 0.3 1.0 0:09.04 pvedaemon worker
3109723 root 20 0 10.2m 6.0m 3.8m R 0.3 0.0 0:00.66 top -em -co%CPU
1 root 20 0 24.0m 14.8m 10.4m S 0.0 0.1 25:56.26 /sbin/init
2 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:01.33 [kthreadd]
3 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [pool_workqueue_release]
4 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-rcu_gp]
5 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-sync_wq]
6 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-kvfree_rcu_reclaim]
7 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-slub_flushwq]
8 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-netns]
10 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/0:0H-events_highpri]
13 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/R-mm_percpu_wq]
14 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:13.69 [ksoftirqd/0]
15 root 20 0 0.0m 0.0m 0.0m I 0.0 0.0 3:42.83 [rcu_preempt]
16 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [rcu_exp_par_gp_kthread_worker/0]
17 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.39 [rcu_exp_gp_kthread_worker]
18 root rt 0 0.0m 0.0m 0.0m S 0.0 0.0 0:03.82 [migration/0]
19 root -51 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [idle_inject/0]
20 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [cpuhp/0]
21 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [cpuhp/1]
22 root -51 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [idle_inject/1]
23 root rt 0 0.0m 0.0m 0.0m S 0.0 0.0 0:03.90 [migration/1]
24 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:09.40 [ksoftirqd/1]
26 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/1:0H-events_highpri]
27 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [cpuhp/2]
28 root -51 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [idle_inject/2]
29 root rt 0 0.0m 0.0m 0.0m S 0.0 0.0 0:03.82 [migration/2]
30 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:09.20 [ksoftirqd/2]
32 root 0 -20 0.0m 0.0m 0.0m I 0.0 0.0 0:00.00 [kworker/2:0H-events_highpri]
33 root 20 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [cpuhp/3]
34 root -51 0 0.0m 0.0m 0.0m S 0.0 0.0 0:00.00 [idle_inject/3]
35 root rt 0 0.0m 0.0m 0.0m S 0.0 0.0 0:03.80 [migration/3]

Idk if I'm pasting the right thing.
 

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Show output of top during a power surge (in code block, as Impact pointed out).

In the graphs you posted of PVE host nothing stands out (Maybe higher than normal Server Load than to be expected from such an inactive system).
Maybe look at NW traffic too. This can also consume more power.

Also show graphs for the HA VM - and also show Disk IO & NW.

In the end you will find a correlation to some activity.

What peripherals USB or other are attached to the host? What storage are you using?

I imagine you have a power meter you are monitoring on the host. Are you sure nothing else (except that single host) is attached to that socket?

andyB2018 said:
As far as I remember I did move HA to another PVE and shutdown it on the actual host.
Click to expand...
Clustered? Shared storage? NFS? Replication?
 
gfngfn256 said:
In the graphs you posted of PVE host nothing stands out (Maybe higher than normal Server Load than to be expected from such an inactive system).
Click to expand...

Periodic spikes are abt. 45 sec apart (~ 27 events per 10 minutes). Graphs only have a resolution of 60 sec if you zoom in.
Because of undersampling you can not find something repeating in a 45 sec period.

Of course from time to time a power spike could randomly hit a measurement of cpu usage but that would not give a nice pattern because lack of synchronization of boh events.

I would run top and wait for that power spikes.
From power graph you know wall time when they occured and intervall. So you can calculate/guess when next events should happen.
PVE host is sufficent as cpu usage of vm will be reflected in it's kvm process anyway. If you find spikes in kvm process of a certain vm, you can dive deeper an run top inside that vm.
 
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