Automated full-disk backup on Linux/Ubuntu

By Atomstar on Friday 4 October 2019 18:14 - Comments (5)
Categories: Linux, RaspberryPi, Views: 2.922

Now that I'm storing my valuable smart home data (;)) on Raspberry Pi I need a backup in case something goes wrong, most notably a power failure.

I settled on a full-disk rsnapshot incremental backup scheme, combined with explicit influxdb backup which seems to work nicely.

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Tunnel Apple AirPlay/Bonjour across zones in OpenWRT Firewall

By Atomstar on Friday 20 September 2019 21:20 - Comments (2)
Categories: Linux, Security, Views: 1.853

I've separated my wifi on my OpenWRT (18.06.2) router (Netgear R7800) in a guest zone and a lan zone for security purposes (well not really, I did it because it was possible). One service I want to allow from guest -> lan zone is Airplay, which uses multicast traffic (Bonjour). It turns out to be very simple to forward Airplay somewhat difficult to diagnose or get this working. In the end I made the AppleTV part of two zones by connecting LAN to local zone and WLAN to guest zone.

Some required steps include (but are not sufficient):
  1. Install avahi-utils, avahi-dbus-daemon, libavahi-client and libavahi-dbus-support as suggested by this post
  2. Forward ports from guest -> lan as listed by Apple
  3. Power cycle/reboot router, AppleTV, and clients (just to be sure)
  4. Profit! --> still doesn't seem to work stable
Unfortunately, I was not able to get this working with my Pioneer VSX-510 which supports AirPlay (v1) natively. Below I note some more details.

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Upgrading Macbook SSD with Sintech m.2 adapters

By Atomstar on Saturday 14 September 2019 14:16 - Comments (7)
Category: Mac, Views: 2.998

Since storage upgrades are quite expensive for MacBooks, there are third-party adapters that allow using m.2 SSDs on Apple's proprietary connector. Here I describe two of these connectors of Sintech.

Summary: the short Sintech adapter is 1.1mm thinner, which also fits in a 13" MacBookPro12,1, the long version does not fit. For a MacBookPro11,2, both the short and long adapter fit. I don't see a reason to buy the long (or rather: thick) version.

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Measuring calibrated Hue energy usage via bridge

By Atomstar on Sunday 4 August 2019 11:21 - Comments (1)
Category: Smarthome, Views: 818

I'm trying to break down where my household electricity usage goes, and lighting is one rather difficult to quantify since there are many devices that have somewhat irregular usage patterns. To alleviate this, I wrote a script to query the Hue (compatible) bulb brightness from the Hue bridge, convert this to power via brightness-to-power calibration curves, and store this to InfluxDB.

I also documented this along with the script at Github.

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InfluxDB retention policy and data downsampling

By Atomstar on Saturday 15 June 2019 12:52 - Comments (1)
Category: Linux, Views: 2.164

Goal: set up data downsampling scheme on existing collectd data.

This article elaborates the official InfluxDB guide here (https://docs.influxdata.c...wnsampling_and_retention/)
where we already have a database with existing measurements that we want to

I'd like to downsample my collectd data on ping, memory, load, etc. data from
two machines. I only want high (minute) time resolution for a few days, then
downsample to save space.

  • instead of using different field/measurement names (e.g. mean_value in ping_hourly), one can use the same measurement and field name to make querying more easy.
  • using grafana variables, one can use dynamic retention policy (RP) use, e.g. use the right RP for the right time range

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