Pihole always in highload all of a sudden

[zakhooi]

Expected Behaviour:

Pihole should run without showing load is in highload on the dasboard.

• OS: Raspbian latest version:
  Linux piholeRPI5 6.6.74+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.74-1+rpt1 (2025-01-27) aarch64 GNU/Linux
• Running native not in a container or VM

Actual Behaviour:

Continuous highload (Red dot is shown)
It wasn't like it before, there was no upgrade done, it's just all of a sudden this happened.
It's affecting DNS resolving performance so users on the network experience 'slow internet' because of this.

Debug Token:

https://tricorder.pi-hole.net/lQUIhBDH/

Thanks in advance for your help

[Bucking_Horn]

Pi-hole just reports high load conditions, it doesn't necessarily cause them itself.

Did you check which process is actually consuming the most CPU?

Also, you seem to run Pi-Alert next to Pi-hole.
Is Pi-Alert monitoring Pi-hole's DNS service, and if so, how often would it send a DNS request?

[zakhooi]

The strange thing is that htop doesn't show a high load at all. (see screenshot)
Yet, pihole's performance is slow because of this issue, thats what is happening.
As far as I know Pialert is not moniotring pihole's DNS service. I didn't change anything on either configuration but this problem showed of all of a sudden.

[Bucking_Horn]

You should check I/O load as well.
(Try htop's I/O tab.)

[rdwebdesign]

@zakhooi

The strange thing is that htop doesn't show a high load at all.

Actually, the kernel reports load is above 4:

(this is considered more than 100% for a Raspberry Pi 5).

As Bucking_Horn said, this can be related to I/O load.
Try iotop or a similar tool.