At approximately 1 PM PST yesterday ( Sept 5th ) the platform suffered an outage that impacted a number of sites. We detected the issue within 3 minutes, and the total degradation was resolved within 30 minutes. Many sites continued to serve content via our Global CDN caching layer during the outage. The main cause was a deployment to our edge layer that purged one of our main (route) caches too aggressively. As part of improving our platform we deploy code multiple times a day with many layers of testing and protections to avoid such outages. We rarely modify our edge layer. We performed a post mortem of yesterday's incident and have added multiple layers of protection to prevent this from happening again. Such changes in the future will invalidate the caching more slowly, and will provision extra capacity in order for the cache to warm up faster.