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Re: Possibly moving Debian services to a CDN

This one time, at band camp, Simon Paillard said:
> Hi,
> We already have a network of almost 400 packages mirrors around the world.
> Using http.d.n, provides the CDN layer (not as much as optimal as anycast), so
> we don't need to sort ourselves peering issues etc.

The mirrors do a very good job of being near to our users in most cases
(we have had some difficulty with things like security mirror coverage,
but that's not your issue).  I know many people are happy with http.d.n,
but you have to understand that it's not the same thing at all as a CDN -
it's a single host, and it's in a single location.  Time to first byte
will still suffer if you're coming from Australia.

> > We can do a home-brewed CDN -- that, after all, is what the various
> > services referenced in the original message are.  But one of the
> > commercial CDNs will have better performance and better load distribution
> > than one can do with software-only solutions without the peering setup and
> > data center distribution.
> * Commercial CDN have no knowledge of debian archive datamodel and
> constraints, which leads to inconsistency (and consequently hash sum dismatch).
> Or this would imply just disabling caching for problematic files, or change
> apt/dak so that the archive is less impacted by synchro atomicity issues.

Or do things like set long cache time on all files, and invalidate the
cache on the metadata files once sync is complete.  There are ways to
solve those issues, just as there are ways to solve them when we're
transferring them with rsync.

> * My own experience is different, http.d.n redirects to ftp2.fr, which i got
> 10,2Mo/s, while cloudfront.d.n (Amazon) gives 5Mo/s.

This is an important data point.  If cloudfront is outperformed by our
current mirror infrastructure, it becomes less appealing.  After all,
we're trying to make things better, not worse.

|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran@debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |

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