On Friday, July 14th, we became aware of an infrastructure issue affecting file access and file backups for some sites on Pantheon. We developed and deployed a fix to permanently resolve the issue.

Over the past several weeks, we have been effecting improvements in our filesystem architecture. These improvements ultimately offer better performance and increased reliability. Specifically, the new architecture allows us to better respond to increases in demand, better isolate failure scenarios, and better manage system updates.

Unfortunately, an element of the new configuration did not perform as expected under specific use-cases, despite our previous load testing. Specifically, the TLS-based secure session negotiation degraded under an widely varied production workload. Once we narrowed in on the specific use-cases and identified the root cause, we were able to reconfigure that component, and return the platform to stable operation. We are confident this new configuration is stable and the improved filesystem architecture will scale to meet the future demands of the platform.

We take reliability and performance seriously. We understand file access is core to all sites on the Pantheon platform. We apologize for any inconvenience and are committed to continually improve the reliability and performance of the platform to meet and exceed your needs.