What does virtual docker image size mean?

Question

As you type, docker imagesit will show you which images are available locally and other information. Part of this information is virtual size. What it is?

I found a little explanation in GitHub Issues # 22 on docker , but this is still not clear to me. I really would like to know how many bytes need to be downloaded and how many bytes are required on my hard drive.

In addition, the Docker Hub 2.0 has one more piece of information. When you look at the Tags page of an image, a different value is displayed. At least, this, apparently, is always much less compared to the information provided docker images.

Answer 1

“Virtual size” refers to the total disk size of all the layers that make up an image. For example, if you have two images, app-1and app-2, and both are based on a common distroimage / layer, the total size of which is 100 MB, and app-1adds an additional 10 MB, but app-2adds an additional 20 MB, the virtual sizes will be 110 MB and 120 MB, respectively. but the total disk usage will be only 130 MB, since this basic level is shared between them.

The transfer size will be smaller (in most cases, very little) due to gzip compression applied to layers during transit.

, https://github.com/docker-library/docs/blob/162cdda0b66dd62ea1cc80a64cb6c369e341adf4/irssi/tag-details.md#irssilatest, . , ( ) irssi:latest 261,1 , "Content-Length" ( ) 97,5 , , , , , 125.1MB 51.4MB "Content-Length" (, , , debian:jessie, ).

irssi:latest

• : 261.1 MB (261122797 bytes)
• Total v2 Content-Length: 97.5 MB (97485603 bytes)

(13)

6d1ae97ee388924068b7a4797d995d57d1e6194843e7e2178e592a880bf6c7ad

• : , 04 2015 19:27:57 GMT
• : 1.8.3
• : 125.1 MB (125115267 )
• v2 Blob: sha256:d4bce7fd68df2e8bb04e317e7cb7899e981159a4da89339e38c8bf30e6c318f0
• v2 Content-Length: 51.4 MB (51354256 bytes)
• v2 : , 04 2015 19:45:49 GMT

8b9a99209d5c8f3fc5b4c01573f0508d1ddaa01c4f83c587e03b67497566aab9

...