> Approximately 30% of our EC2 instances, which were responsible for running applications, databases and supporting infrastructure (including some components specific to the Bamboo stack), went offline
Combined with the incident report from amazon, does this mean that 30% of Heroku instances were in a single availability zone? That would be troubling.
Why is that troubling? There are currently 5 AZs in the region (there were fewer when they designed their service), so the best they could possibly do is 20% of their instances in each. Losing 20% of their instances instead of 30% isn't much of an improvement.
What they need is failover between regions/clouds and external monitoring, not a slightly better allocation of instances between AWS AZs in one region.
Combined with the incident report from amazon, does this mean that 30% of Heroku instances were in a single availability zone? That would be troubling.