What's the actual number of 9s for the major cloud services these days?
My impression from their PR seems to mismatch the number of outages and issues lately.
My impression from their PR seems to mismatch the number of outages and issues lately.
For an individual instance, they only promise 90% availability.
What you're talking about with provisioning capacity is a totally different matter. Provisioning availability is not guaranteed (unless you purchase reserved instances) and there are frequently periods where certain instance types are not available in certain AZs, though they do try to resolve that as fast as practicality allows them to. It really stinks sometimes though - especially if you get into a situation where something fails in your autoscaling group and there is no capacity available for a replacement instance. Usually you can get around that though by making sure your ASG is set up for multiple AZs, or worst case changing instance types (though that can be problematic in it's own way).
source: I used to work for AWS Support.
I think people sometimes forget that the cloud isn't magic, and a sudden burst of requests for new instances needs somebody to actually rack up some servers.
now I wouldn't go as far as to say outages are the normal state of thing, but cloud trades high nines for cheap redundancy. a raid for compute, if you will, and as such a single zone deployment is going to have outages.
(and then there's soft layer which has multiple unplanned sev1 per week)
Due to network failures etc. number visible to customers is unlikely to be going to be much higher than that in cloud services.