ostree/fedora atomic and impact on the mirror network

[Florian Weimer]

On 03/11/2014 02:34 PM, Martin Langhoff wrote:
> On Tue, Mar 11, 2014 at 9:10 AM, Colin Walters <walters at verbum.org> wrote:
>> Remember OSTree is a content-addressed object store (like git), not a chain
>> of deltas (like Subversion, and other systems out there such as Chromium
>> Autoupdate, and Docker).
>
> Ouch -- so updates fetch EVERY file regardless of whether it has
> changed between the snapshot installed and the target snapshot? That
> is kind of bad.

It only downloads objects which are new, e.g. files that have changed, 
or directories which contain a change (perhaps indirectly).  This is 
still a lot of HTTP requests, so it is very slow unless you happen to 
have a local mirror.

> Are you aware of the work done on OLPC's os-builder, which used rsync
> "informed" by a per-snapshot metatada file?

Plain rsync is usually not deemed suitable for distributing things 
because of the server-side overhead.  zsync (rsync algorithm with a dumb 
server) might work, though.

-- 
Florian Weimer / Red Hat Product Security Team