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Upstash: Fly.io Upstash Redis service distruption (FRA region)
Upstash reported a major degradation affecting some Fly.io Redis databases in FRA, with increased latency or timeouts. It started at 2026-05-11 15:05 UTC and resolved at 2026-05-11 18:22 UTC, lasting 3 h 16 min. The postmortem described Redis processes stalling inside a logging syscall; the supplied root-cause explanation is truncated.
Machine-written from the archived incident (Sol). Check the timeline before relying on it.
Timeline of updates
- investigating
Some databases may experience increased latency or timeouts in Fly.io’s FRA region.
- investigating
We are continuing to investigate the issue.
- investigating
We are working with Fly team to investigate the root cause.
- resolved
The incident has been resolved. We are working with Fly team on RCA.
- 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.
Rewindex changes for this incident
- Major incident: Fly.io Upstash Redis service distruption (FRA region) 2026-05-11 15:05 UTC
Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab). Upstash profile · Recent Upstash incidents · Markdown · JSON