Eric Avdey eiri

$ erl -noshell -eval 'erlang:display(erlang:system_info(system_version))' -eval 'init:stop()'
"Erlang/OTP 20 [erts-9.1.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]\n"

How to use COPY in CouchDB

Create new db

$ http put :5984/names --auth admin:secret
{
    "ok": true
}

Install Prometheus on Debian

install gosu

just to not wrestle with sudo and exec

$ sudo apt-get update
$ sudo apt-get install gosu

Create prometheus user

Bench CPU and disk of VM debian/jessie64

Setup

Host: MBP Intel i7 4 cores, RAM 16GB. Guest: 1 cpu, 4096 memory. Surprisingly this is better than more memory and/or more cpu cores setup.

Compare --ioapic and --acpi flags.

TL;DR

Turn both on. Even though ioapic shouldn't be relevant on 1 cpu and acpi said to be better off for perf boost,

Prereq

Running docker, couchdb:2.1.1 image, httpie. Create dir data and etc. Place local.ini in etc

Run

$ docker run --rm -it -d -p 5984:5984 -p 5986:5986 -v $(PWD)/data:/opt/couchdb/data -v $(PWD)/etc:/opt/couchdb/etc/default.d couchdb:2.1.1
250179e806b370fea7cd99e5fa7bfae5a4586b3bfda6bded5f956424346449e2

How Couch query parameters work

This is a table showing a relationship between CouchDB view and _all_docs query parameters start_key, end_key, descending and inclusive_end. Obvious things to notice: 1) Start key always included 2) inclusive_end doesn't affect starting key 3) from A to B asc not equal from B to A desc.

 start_key | end_key | inclusive_end | descending |
                                                    [ 1 | 2 | 3 | 4 | 5 | 6 ]
 null      | null    | true          | false      |   1 ----------------> 6

	[Erln8]
	color=true
	banner=false
	default_config=default
	system_default=r20

	[Repos]
	default=https://github.com/erlang/otp.git

	[Erlangs]

	FROM bitnami/minideb:stretch

	MAINTAINER Eric Avdey <[email protected]>

	ENV ESL_REPO=http://packages.erlang-solutions.com/debian \
	ESL_DIST=esl-erlang \
	ESL_VER=1:19.3.6

	WORKDIR /tmp

	package main

	import (
	"crypto/hmac"
	"crypto/rand"
	"crypto/sha1"
	"encoding/hex"
	"fmt"
	)

	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<dict>
	<key>Label</key>
	<string>DockerSystemPrue</string>
	<key>Program</key>
	<string>/usr/local/bin/docker system prune -f</string>
	<key>StartCalendarInterval</key>
	<dict>