Denys Digtiar duemir

Retrieving Docker Image Sizes

There are two metrics that are important to consider when discussing the size of Docker images.

Compressed size - This is often referred to as the wire size. This affects how fast/slow images can be pulled from a registry. This impacts the first run experience on machines where images are not cached.
Uncompressed size - This is often referred to as the size on disk. This affects how much local storage is required to support your Docker workloads.

The example commands shown below will work on Windows, MacOS, and Linux.

How to Measure the Compressed Size

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

	-- Matthew Brecknell @mbrcknl
	-- BFPG.org, March-April 2015

	-- With thanks to Conor McBride (@pigworker) for his lecture series:
	-- https://www.youtube.com/playlist?list=PL44F162A8B8CB7C87
	-- from which I learned most of what I know about Agda, and
	-- from which I stole several ideas for this talk.

	open import Agda.Primitive using (_⊔_)