2021-08-11

Complexity

tags: data complexity

Power Outage

While I was away for a few days, there has been our yearly power outage. Once or twice a year we are gently reminded that working power outlets are not a given --- even in our location in the middle of the "First World". For about half an hour grid electricity ceased. That is not really worth mentioning. All of my electronic maker style gadgets started normally, when power was restored.

With one exception. InfluxDB would not start. The other components of this multilayer hardware and software adventure were running normally: the controllers, power supply, the rs485 bus and the bus master collecting data, mosquitto, telegraf, and grafana. Except that the browser received a

> Bad Gateway!

Error message and did not show any data in any panels.

The next morning I made some experiments, but to no avail. I decided to downgrade influxdb

> [DOWNGRADE] influxdb:amd64 1.8.9-1 -> 1.6.4-1+deb10u1

In other words, from the latest newfangled release available at influxdata.com to the one that comes packaged with Debian 10. Needless to say, it worked. I don't have an explanation, but my knowledge in this part of the game is rather limited.

Obvious Conclusions ...

So maybe for this particular system and my exact environment I might want to reconsider, whether the latest version gives me anything I absolutely must have. And the same question goes for grafana and telegraf.

And just maybe I should re-check the details involved in backing up the database as well.

... and not so obvious ones

What if I loose all these nice data points? All the way back up to 10 years? Well.

It would hurt, and I would make myself a clown not having tested backup.

I would be unable to show off the fancy graphs to my wife and to whoever cares enough to see them.

However, the world would not come to a grinding halt.

Once again I'm very glad, that I have decided to not derive any automatic action from these data points. While curiosity might kill a cat here and there, it is my firm believe, that complexity will kill us all some day.

Cheers,

~ew

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