jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

Gen2ly

#!/bin/bash
# Convert Markdown to Wordpress blogging format

# Required program(s)
req_progs=(ascii2uni pandoc)
for p in ${req_progs[@]}; do
  hash "$p" 2>&- || \
  { echo >&2 " Required program \"$p\" not installed."; exit 1; }
done

shamil

How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

AlexeyDemidov

# save this file in /etc/default/unicorn_app
USER=app_user
APP_ROOT=/srv/app
RVM_STRING=2.2.4@app_gemset
RACK_ENV=production
UNICORN_OPTS="-D -c /srv/app/shared/config/unicorn.rb -E production"
DAEMON=unicorn

kuanghan

Setting up docker to run in a PRIVILEGED LXC container

Set up a privileged container

Create container

Let's call the container docker_test1.

$ sudo lxc-create -t download -n docker_test1
...
Follow the prompts on the screen to set up the new container.

superseb

RKE2 commands

• Updated on May 29 to accommodate etcd container not having /bin/sh available anymore.

Install

curl -sL https://get.rke2.io | sh
systemctl daemon-reload
systemctl start rke2-server