Distributing filesystem images and updates with casync

Posted Jun 29, 2017 14:05 UTC (Thu) by walters (subscriber, #7396)
Parent article: Distributing filesystem images and updates with casync

For the OSTree case, the expectation is that CDNs serve deltas. That's existed for years now. Yes, you can hit the individual fetch path when doing downgrades and the like, but with HTTP2, the overhead of individual requests is a lot lower. Still though, I don't think it's fair to ding OSTree for the individual fetch problem when deltas exist.

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Distributing filesystem images and updates with casync

Posted Jun 29, 2017 15:16 UTC (Thu) by mezcalero (subscriber, #45103) [Link] (1 responses)

Yeah. My blog story mentions the deltas actually.

Distributing filesystem images and updates with casync

Posted Jun 30, 2017 12:33 UTC (Fri) by walters (subscriber, #7396) [Link]

Yes, but you implied in your post that there was an issue, and the article author took that literally (it looks like without doing their own research, which is understandable).

Basically I think this sentence should just be deleted:

> OSTree's method of serving individual files would be detrimental to the performance of content distribution networks if there were a plethora of small files, as synchronization will hammer the CDN with multiple HTTP GET requests.

Now, a definite OSTree issue is *managing* deltas, but for the OS update case, it's really really easy to just run `ostree static-delta generate` before publishing. When you involve multiple branches, managing deltas between them gets a little harder but it's just a matter of scripting.