Only half-dead?

[JonInAz]

I installed OSPi on a Rpi A+ with an 8GB uSD about 2 weeks ago.  Ran it/played with it on the desk (with attached keyboard/monitor) for a day or two, then a week using ssh and the web.py interface to the Interval program.  All is well.  Last Sunday I installed it in-situ, and through Tuesday was able to access it just fine.

Tonight, not so well.  Was unable to access the Interval web page, nor to ssh.  Rebooted (cycled power), got to the Interval home page (actually logged in and started a manual program), but after that no further (page access times out).  No ssh access.  Have rebooted several times since.

–  OSPi home page (http://xxx.xxx.xxx.xxx) comes up immediately when I try, every time.  So I know the OS is running, and the IP address is correct.  Unless that is a cached page…

–  Interval login page (http://xxx.xxx.xxx.xxx:8080) comes up sometimes, after several minutes, other tries times out.  Have not been able to login, except that first time, when I did not get past turning on a circuit.  But I *did* turn on a circuit, and it is now off.  (Does the Interval program start circuits if the OSPi is rebooted during a scheduled run?)

–  ssh has not worked at all tonight (attempting to login as “pi” user; perhaps I should have created another account?)

–  have been unable to ping it tonight (although I was successful in the past)

Any ideas?   This weekend I’ll unmount it and put it on a desk with a keyboard and monitor.  I did install avahi last weekend after I mounted the board in it’s cubby – perhaps that had some adverse side effects.

Jon

[Ray]

My suggestion is to unplug Pi from the OSPi board, and try to see if the issues persist. This way you can isolate problems with Pi vs problems with OSPi. Keep in mind that the microSD card might have gone bad causing the symptoms you see.

[JonInAz]

Thanks.  Yes, I’ll try that this weekend.  This morning I tried to connect to the default webpage (at port 80 rather than Interval at port 8080)  from a different computer, one from which I’d never accessed that page, and it timed out.  So I think my assertion that I was successfully connecting to the Pi was wrong – it must have been a cached page on the other PC.

It occurs to me there was another strong clue, of perhaps something starting to go south – I recall now that the last time that I was successfully connecting to the Pi, there were some intermittent delays communicating with it.  For example, I had ssh’d into it to do some browsing (looking at the OSPi code), and every once and a while I’d get a delay – in the ssh terminal, there’d be no echo of the typed characters for several seconds, and then they’d all echo back at once.   This occurred not long after I’d installed avahi, and I was thinking “that single core processor just can’t keep up.”   But that could have also been a symptom as you suggest of the SD having intermittent errors.

Will I find linux system logs on Raspbian?

More later…

 

[JonInAz]

Moved the Pi out of it’s cubby (a panel on a cabinet in the garage), and all is well.   Nothing in the syslogs to suggest a fault.  I’ve concluded my issue is poor wifi at that location.   I did test run it for a while there before installing it, but something has changed – either the sensitivity of the receiver has degraded, or perhaps one of my neighbors has added an access point.  (I didn’t move anything into the wireless line-of-sight.) I took my laptop out to that location and scanned the wifi, and was surprised both at the low power of my network, and that I could see 6 neighbours networks, all at power levels comparable to my network.  I’ll have to rethink my networking approach.  A remote or higher-gain antenna, or use powerline networking.  I have a couple of other WiFi dongles to try, in case it is degraded transceiver sensitivity.

What I should have done:  prior to mounting the OSPi, I should have scanned WiFi and captured the networks and signal levels.  Had I done so, I’d have some data to quantify the change, and possible have known I was on the edge of reasonable performance.

Here’s the linux scan command I used:

sudo iwlist wlan0 scan

 

 

[JonInAz]

Moved an Access Point to the vicinity of the garage and all is well.   Wifi scan now that I’m connected with it in the proper location shows the “new” AP at “Quality 100/100    Signal Level 98/100”, whereas the original AP shows “Quality 97/100    Signal Level 44/100”   Not sure what the metrics are (the man page for iwlist doesn’t say) but I’ll deduce the Quality metric is not particularly useful.

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