SBC long term stability

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Patrick
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Re: SBC long term stability

Postby Patrick » Fri Apr 16, 2010 8:43 am

This is a proper use for wpa_cli, but as with all code, it's easily possible that there are bugs. I can try updating to a newer version of the wireless tools - maybe this issue has been fixed. I will also at some point implement a watchdog system for restarting important system services - this will probably be exposed in the web interface so users can control which processes are watched/automatically restarted. No timeline on this though I'm afraid.

Thanks for the help in tracking down this issue, and I hope that your SBC is stable from now on.

-Patrick

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Re: SBC long term stability

Postby pythoncoder » Mon Apr 19, 2010 4:53 am

Hi Patrick, as something of a postscript to this dialogue I thought you might be interested in the following observations. I installed this watchdog script on both of my SBC's.

Code: Select all

#! /bin/sh

# Restart the wifi if it goes down
# log the event in /tmp/utime.txt

while [ true ]
do
   sleep 60
   if ! ps ax | grep [w]pa_cli > /dev/null
   then
      rm /var/run/wpa_supplicant/wlan0
      /sbin/wifi restart wlan0
      uptime >> /tmp/utime.txt
   fi
done
As you can see it appends a record of its activities to a file. Both SBC's run the full version of the firmware (and the Watchdog script), #1 runs my C program but #2 runs only the watchdog. My Wifi is turned off every night. The outcome was as follows:

SBC #1
# cat utime.txt
23:04:19 up 1 day, 11:20, load average: 1.45, 0.42, 0.19
23:42:24 up 1 day, 11:58, load average: 1.69, 0.51, 0.23
#

SBC #2
# cat utime.txt
21:26:30 up 1 day, 9:54, load average: 0.32, 0.14, 0.10
07:00:07 up 2 days, 19:28, load average: 0.67, 0.22, 0.12
08:49:18 up 2 days, 21:17, load average: 0.46, 0.17, 0.11
22:15:33 up 3 days, 10:43, load average: 0.29, 0.12, 0.05
07:33:25 up 3 days, 20:01, load average: 0.15, 0.11, 0.09
#
A couple of things strike me from the above. Firstly the two SBC's experience problems at different times (both were started within minutes of each other), so it would appear that they are not being influenced by external events. Secondly wpa_cli seems to fail when the wifi is down, which rather rules out issues with my Wireless Access Point! (I haven't a precise record of when my Wifi is up, but it's never up before 9am).

Regards, Pete

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Patrick
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Re: SBC long term stability

Postby Patrick » Mon Apr 19, 2010 10:06 am

Good to know, thanks for all the input.

-Patrick

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Re: SBC long term stability

Postby pythoncoder » Sun Sep 26, 2010 3:50 am

Just a note to let you know. Aside from powering it down once to move it to its permanent location this device has been running 24/7 since April. Faultless stability :)

Regards, Pete


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