Fly.io Upstash Redis service distruption (FRA region)

Postmortem

Major impact

Started

Lasted 3h 17m

View official incident ↗

Updates

  1. Postmortem

    On May 12th and 13th at various times, a subset of Upstash Redis instances on [Fly.io](http://Fly.io) experienced intermittent hangs and elevated error rates. The Redis process would stall inside a logging syscall — alive but not making progress — which made the issue hard to spot from our usual telemetry. After investigating with Fly's team, we identified the root cause as a bad interaction between a recent guest kernel update on Fly's newer machines and an upstream Cloud Hypervisor bug \([cloud-hypervisor#7672](https://github.com/cloud-hypervisor/cloud-hypervisor/issues/7672)\) affecting log writes from inside the VM. We mitigated by disabling the affected logging paths, and Fly has since rolled out a hypervisor-side patch, fully resolving the issue. No data was lost. Sorry for the disruption.

  2. Resolved

    The incident has been resolved. We are working with Fly team on RCA.

  3. Investigating

    We are working with Fly team to investigate the root cause.

  4. Investigating

    We are continuing to investigate the issue.

  5. Investigating

    Some databases may experience increased latency or timeouts in Fly.io’s FRA region.