Linux (or macOS) related

InfluxDB retention policy and data downsampling

By Atomstar on Saturday 15 June 2019 12:52 - Comments (1)
Category: Linux, Views: 643

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
keep.

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.

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Speeding up an nginx webserver

By Atomstar on Saturday 9 February 2019 12:43 - Comments (6)
Categories: Linux, RaspberryPi, Views: 2.474

After properly securing my nginx webserver, I tweaked the cache and connecting settings to improve performance as measured by www.webpagetest.org which I documented below.

The results are as follows, I achieved a 3.2x faster document ready timing, and reduced bandwidth by 18x.

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Setting up an A+-grade nginx SSL server

By Atomstar on Sunday 27 January 2019 15:25 - Comments (7)
Categories: Linux, RaspberryPi, Security, Views: 3.718

Because I don't want to expose smarthome dashboards (like domoticz or grafana) directly to the internet, I've set up a separate server to publish data beyond my local network. For this I've chosen nginx using let's encrypt certificates renewed by certbot, enabling hsts and fixing the logjam vulnerability.

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StrongSwan IKEv2 VPN on Raspberry pi

By Atomstar on Monday 24 December 2018 01:08 - Comments (6)
Categories: Linux, RaspberryPi, Security, Views: 5.305

Guide to set up road warrior VPN server (i.e. road warrior = mobile clients connecting to static server, vs e.g. site-to-site connection) using IKEv2 using strongswan on a raspberry pi. This guide is largely based on this digitalocean guide combined with ready-made strongswan configurations.

Update 20181224: added algo VPN configurator
Update 20190223: added cipher analysis / recommendation, clarified eth0 interface use on server, ESP/AH forwarding, added password generation one-liner.

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Connecting sensors to Rpi (2/3)

By Atomstar on Sunday 2 December 2018 18:07 - Comments (0)
Categories: Linux, RaspberryPi, Smarthome, Views: 1.523

Here I describe the various sensors I connected to my RPi. Specifically:
  1. Kaifa DSMR 4.0/4.2 smart meter
  2. SMA sunnyboy PV inverter
  3. Honeywell Evohome thermostat
  4. Sensus analog water sensor
  5. Landis+Gyr Ultraheat digital 7-segment LCD heat meter


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