Cubieboard 2 unresponsive when swapping

[lazerdye]

I have a cubieboard2 running Armbian_4.5_Cubieboard2_Debian_jessie_4.2.3.zip and when I ran a seemingly innocent "npm search" command, the system became extremely slow. It responded to pings, but SSH commands were taking many minutes to complete. I was able to grab a screenshot of "top" while it was in this state (attached).

Root is on SD, I set up a 1GB swap partition over SATA.

My questions are:

* Is setting up a 1GB swap partition over SATA a bad idea?

* Why do all of the processes suddenly report 100% CPU when main memory runs out?

* How can I prevent this in the future?

* Is there any other diagnostics or tests that can help determine the root cause?

 

Thanks,

Terence Haddock

 

[zador.blood.stained]

"48.4 sy 51.5 wa" on 3rd line partially answers your second and fourth questions - SATA interface on A20 is slow and inefficient, so swapping combined with running torrent client results in this - CPU is processing SATA requests and waiting for I/O operations (and if you have mechanical HDD, seek time when multiple programs access different files also affects this).

 

So in your case using swap on SATA is bad idea, using no swap (if possible), zram or swap on SD card may be better.

[lazerdye]

Thanks, I'll just disable swap on this machine, and monitor the memory usage.