npm, PyPi overtake CPAN

Anthony Lucas anthonyjlucas at
Mon May 27 10:45:03 BST 2013

Fair point.

Although, working closely with some fairly large CDNs in the past, I just
*have* to point out that disaster / failure plans should never ever rely on
them. Some companies seem to be confused on this.

Seriously, CDNs are for speed, with the side effect (not feature) of
sometimes masking outages.

They don't solve them, they just make them harder to measure.
 On Friday, May 24, 2013, Nicholas Clark wrote:

1) in an online environment, just a URL to a master site is a single point
> of
>    failure. Start to chain enough dependencies, and however reliable they
> are
>    at building and testing, it doesn't work if you can't download the code
>    because one server is down

How true is that these days though? PyPi isn't a single server that can go
down. It's now running on a CDN[1], and even in the event of a failure of
the origin, the CDN will keep serving last known good (much like the
situation with a mirror and the master mirror failing.)

Obviously it's not perfect - infrequently pulled traffic might not be on
the CDN when a failure occurs (I suspect people on this list who work for
fastey can provide us the exact details if they wanted) but the advantages
of instant update of changes to all 'mirrors' are not to be sneezed at.

I guess I'm saying its not as cut and dry as it used to be.


[1] as of about ten hours ago -

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