Denis Zhdanov deniszh

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

In August 2007 a hacker found a way to expose the PHP source code on facebook.com. He retrieved two files and then emailed them to me, and I wrote about the issue:

http://techcrunch.com/2007/08/11/facebook-source-code-leaked/

It became a big deal:

http://www.techmeme.com/070812/p1#a070812p1

The two files are index.php (the homepage) and search.php (the search page)

	# Helper script to turn a single monolithic WHISPER_DIR into one that is
	# allocated based on the shard id (carbon-cache instance name)
	#
	# Take a single WHISPER_DIR such as '/opt/graphite/storage/whisper' and
	# figure out how to divide them up into shards based on the given list of
	# carbon-cache shard instances and replication_factor
	#
	# The output will be multiple text files that can be used with `rsync --files-from=`
	# to copy the right .wsp files to the correct nodes.
	#

	import os
	import os.path
	import sys

	from graphite.render.hashing import ConsistentHashRing

	instances = []
	unwelcome_instances = []
	for arg in sys.argv[1:]:
	unwelcome = False

	GARBD_ADDRESS="gcomm://192.168.1.2"
	GARBD_GROUP="my_snazzy_cluster"