On Tue, 15 Jun 2010 09:49:03 pm M.-A. Lemburg wrote: > As mentioned, I've been working on a proposal text for the cloud > idea. Here's a first draft. Please have a look and let me know > whether I've missed any important facts. Thanks.
I think the most important missed fact is, just how unreliable is PyPI currently? Does anyone know? I know there's a number of people complaining that it's down "all the time", or even occasionally, but I think that we need to know the magnitude of the problem that needs solving. What's the average length of time between outages? What's the average length of the outage? Just saying that there's been several outages in recent months is awfully hand-wavy. [...] > Amazon Cloudfront uses S3 as basis for the service, S3 has been > around for years and has a very stable uptime: > > http://www.readwriteweb.com/archives/amazon_s3_exceeds_9999_percent_u >ptime.php Is there anyone here who has personal experience with Cloudfront and is willing to vouch for it? Or argue against it? We can only go so far based on Amazon's marketing material. One thing that does worry me: > So in summary we are replacing a single point of failure with N > points of failure (with N being the number of edge caching servers > they use). I don't think this means what you seem to think it means. If you replace a single point of failure with N points of failure, your overall reliability goes down, not up, since there are now more things to go wrong. Assuming that they're independent points of failure, that means your total number of failures will increase by a factor of N. For example, if a single edge server in (say) Australia goes down, Amazon might not count it as an outage for the purpose of calculating their 99.99% reliability since the system as a whole is still up, but conceivably Australian users might see an outage (or at least a slow-down). With N servers, I'd expect N times the number of individual outages, with Amazon presumably only counting it as "system down" if all N servers go down at the same time. -- Steven D'Aprano _______________________________________________ Catalog-SIG mailing list Catalog-SIG@python.org http://mail.python.org/mailman/listinfo/catalog-sig
