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ygoe

Totally slow system after running for a day

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I've copied Armbian Ubuntu Focal onto a brand-new SD card and started it on an Orange Pi Zero. This has worked before with the Bionic version. After setting it up and upgrading all packages, I rebooted and everything was running smoothly. Now I've done the same as before but found that the system is totally slow after running for just one day. It's set up to collect data from a 1-Wire temperature sensor and send it to my server. And it lets the green LED blink twice every 30 seconds to show it's still there and has a network connection. The network is connected via Ethernet cable, WLAN is not used.

 

Observation 1: It took half a minute to login the first time today. Manpages take a while to load and even the shell echo isn't instant (up to a few seconds behind).

 

Observation 2: There's plenty of free memory (85 of 245 MB used), swap is like 45 of 120 used. 'top' shows that the process kswapd0 has by far the most CPU usage. Often it's between 5 and 30%, in total it's much more than any other process.

 

Observation 3: The LED should blink twice with a delay of 1 second. It actually blinks once and maybe a second time sometime later. But definitely not within a second. It's a shell script that just calls 'sleep' to wait. So even 'sleep' doesn't return in time here.

 

I've tried to use 'swapoff -a' but it doesn't change anything. It prints "Killed" and then swap still shows up in the output of 'free'.

 

System diagnosis data was uploaded to: (waiting many minutes...) (still uploading... I'll provide the link as soon as it's done)

 

What could be the cause of such misbehaviour? It's like it has aged decades in just one day, doing almost nothing. On a new board and new SD card. Very strange, I've never seen that before.

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Armbian is a community driven open source project. Do you like to contribute your code?
19:56:17 up 1 day,  3:50,  1 user,  load average: 15.19, 14.47, 10.24

and you also ran out of memory. I don't see in the log which process is eating resources ... can you run top or similar when you experience this slowness?

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Oh, I downloaded that image 2 weeks ago. Have to update again. Do I have to copy it to the SD card again or can I upgrade it from the system like 'apt upgrade'? I did the latter just this weekend when I set things up.

 

Igor, you showed the load values. Doesn't that mean that the system is juggling many things in parallel, some of which could just be IO waits so no real CPU activity? The 'free' command said I have plenty of free memory and swap. I looked into top but couldn't see anything especially interesting there besides "kswapd0" taking much CPU time. I'll look again tomorrow. Had to restart the system because nothing worked anymore. At least I could issue a reboot command and didn't have to cut the power.

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9 hours ago, ygoe said:

Oh, I downloaded that image 2 weeks ago. Have to update again. Do I have to copy it to the SD card again or can I upgrade it from the system like 'apt upgrade'? I did the latter just this weekend when I set things up.

 

It is a better idea to start from scratch.especially on Focal. There is a regression that causes the OS after upgrading to be unable to boot. This can be fixed manually though when changing the compression algorythm for the initramfs from lz4 to gzip. Check /etc/initramfs/initramfs.conf (I think it was) file.

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Thank you for the suggestions. I first wanted to see what happens after that reboot. The issues has just gone away. I have not changed anything with the system or software, just rebooted when it was so busy. Since then, the load is constantly low and memory usage is also low. My own client app keeps happily sending its data to the server and the LED timer still works nicely. First a week with LAN connection, now a few days with WLAN only. So whatever it was, it didn't come back and a reboot solved it. Maybe I should set up a watchdog that reboots (not hard-resets, as long as possible) the system on unexpected high load or slow reaction speed.

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