CPU utilisation on raspberry pi

eDeviser · November 21, 2018, 9:11pm

I just noticed that my seafile server spends about 50% of its CPU time on waiting for some IO. I. E. while synchronising some gigabytes of data I had a look to top in the command line and I saw that the CPUs are about 40% idle and 60% waiting.
Nevertheless I can reach upload rates of up to 8 MB/s

Well I wonder if this is normal!? Does any body else haveing the same values for the CPU utilisation?

Here is my setup:
I am running the latest version of seafile server on an Raspberry 3. The server is installed on the microSD card
The seafile-data folder is on a 2.5" HDD which is attached via USB.
My seafile server uses nginx, SQLite and https.
The Raspberry runs at normal clock speed and uses raspian lite.

Cisco · November 21, 2018, 9:49pm

hi
what is the class of your SD card?

shoeper · November 22, 2018, 1:28pm

Make sure nothing writes to the sd, it is slow and the sd will be broken within short time.

eDeviser · November 23, 2018, 9:46pm

Hello and thank you for the hints.

I was just now not able to pull out the microSD card from the rPi.

But I moved the whole installation to the external HDD.
Now the ioWait is about 20%. It varies between zero an 50%.