Aaron Zauner azet

 Collected these for members of our network/NOC/Datacenter 
 infrastructure team. May be of interest to you. Feedback welcome. 
     -- azet (@azet.org)

Optics, high speed/low latency transmissions, long haul connections, undersea cables & physical limits today and in the future:

Tutorial: Everything You Always Wanted to Know About Optical Networking – But Were Afraid to Ask
https://www.youtube.com/watch?v=Y-MfLsnqluM & <Slidedeck>
(Introduction to optics and all relevant topics: fiber types, wavelengths, O,C&L-band, WDM: CWDM vs DWDM, ROADM, amplification, MUX/DEMUX, optical switches, OTN, open line systems, optical taps & splitters, monitoring, dispersion, attenuation, SNR etc)

Check Out these projects, papers and blog posts if you're working on Geo redundant Datacenters or even if you only need to have your software hosted there. It's good to know what you're in for.

  Collected these for a colleague, these have been super useful over 
  the past 15+ years and and will most likely help and/or entertain you. 
  May be extended in the future.
  -- azet (@azet.org)

load balancing

DNS geo & anycast

Super Guide to the `split-window` tmux Subcommand (and Beyond)

Guide overview

tmux, like other great software, is deceptive. On the one hand, it's fairly easy to get set up and start using right away. On the other hand, it's difficult to take advantage of tmux's adanced power features without spending some quality alone time with the manual. But the problem with manuals is that they aren't geared toward beginners. They are geared toward helping seasoned developers and computer enthusiasts quickly obtain the

Recursively download all data within a directory (e.g. images, documentation,..)

..without following links like the index pages ../ or sub-directories
if you want to include sub-directories, change the -l option to >1, depending on how deep you want to follow the paths.

Example:

wget -r -c -np -l1 https://memory.loc.gov/master/mbrs/recording_preservation/manuals/

The URL in the example contains: Library of Congress recording preservation manuals - mostly PDF files on audio (legacy, analog) engineering/equipment; Consoles, Compressors, Pre-amplifiers, Recorders, everything you can imagine from the analog age - that's very en vouge right now in the recording scene/industry.

Options/Parameters explained:

Discogs_ Community's decline of "sell and trade"

Disclaimer

this was originally published in a facebook post as a follow-up to an earlier post on a specific label where I didn't want to go too much off-topic about prices and the decline of the vinyl collector community that runs discogs (entries, updates etc.) similar to Wikipedia authors but also sell and trade - the specific part I was growing concerned over.

This text has been manually converted to reStructuredText aka .rst to provide cohesive sections, text-style and footnotes to the document.

AUTHOR: [email protected] | https://www.discogs.com/user/azet

install vQFX10k on KVM/QEMU for Testing or QA

This vQFX Platform is supposed to be used with vagrant and ships with a few nice fabrics that spin up on the go. But there's a few problems with that - which may not be instantly obvious if you plan on using it for testing or QA in your NetOps department:

This Vagrant configuration relies and only supports virtualization via Virtualbox
- so far no plans have been announced to switch from Virtualbox to another out of the box solution, so you'll have to hack this up a bit. libvirt, kvm/qemu makes this relatively simple, but you have to get familiar with their tools (again).
vQFX comes in two "VMs": a Routing Engine (RE) and a Packet Forwarding Engine (PFE)

this is due to the way the hardware is actually set-up and working on a real bare metal switch or router (same story for vMX). ASICs are supplied in the form of shim kernel modules that make it possible to unit-test more advanced features or do functional testing before deploying on real (ide

Tango Flush - an alternative 'Windows Terminal' color scheme

Screenshot:

How to use or Build:

Seriously? Well copy what you like into your settings.yaml (accessible via the Windows Terminal Settings, too). If you take the color scheme, you might want to take a look at the WSL2 Debian profile as well. I'm most likely writing this for no-one.

	# long running queries:
	SELECT
	pid,
	now() - pg_stat_activity.query_start AS duration,
	query,
	state
	FROM pg_stat_activity
	WHERE (now() - pg_stat_activity.query_start) > interval '5 minutes';

	## active queries and killing them: