ClickHouse incident
We are investigating an issue with CH servers in Azure germanywestcentral region
ClickHouse experienced a minor incident on September 22, 2026 affecting germanywestcentral and eastus2 and 1 more component, lasting —. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Sep 22, 2026, 01:19 PM UTC
Status: Investigating We detected an issue with CHC clusters in some Azure regions. ClickHouse cloud team is investigating. Some operations might be degraded. Affected components germanywestcentral (Degraded performance) westus3 (Degraded performance) uaenorth (Private region) (Degraded performance) australiaeast (Private region) (Degraded performance) japaneast (Private region) (Degraded performance) eastus2 (Degraded performance)
- investigating Sep 22, 2026, 01:21 PM UTC
Status: Investigating Only germanywestcentral Azure region is affected. Affected components germanywestcentral (Degraded performance) westus3 (Operational) uaenorth (Private region) (Operational) australiaeast (Private region) (Operational) japaneast (Private region) (Operational) eastus2 (Operational)
- investigating Sep 22, 2026, 01:31 PM UTC
Status: Investigating Only one Availability zone is affected in germanywestcentral Azure region. The problem affects internal component (ClickHouse Keepers). Some ClickHouse Services in this region may see increased latency on inserts or DDL queries. Affected components eastus2 (Operational) germanywestcentral (Degraded performance) westus3 (Operational) uaenorth (Private region) (Operational) australiaeast (Private region) (Operational) japaneast (Private region) (Operational)
- investigating Sep 22, 2026, 01:49 PM UTC
Status: Investigating The problem is caused by Azure outage in the germanywestcentral region. ClickHouse Cloud team is working with Azure support. Impact: • New ClickHouse services can't be provisioned (appear as stuck in UI). • Some services may experience higher latency due to reduced capacity. Affected components eastus2 (Operational) germanywestcentral (Degraded performance) westus3 (Operational) uaenorth (Private region) (Operational) australiaeast (Private region) (Operational) japaneast (Private region) (Operational)
- identified Sep 22, 2026, 02:57 PM UTC
Status: Identified The Azure team is working on resolution of the issue. The ClickHouse Cloud team will relay any updates related to ClickHouse clusters operation. An excerpt from Azure incident status: "As per our investigation, we believe this stemmed from multiple underlying storage systems becoming unavailable at the same time, which led to attached virtual machines becoming unresponsive, restarting unexpectedly, or being temporarily unavailable. " Affected components germanywestcentral (Degraded performance)
- monitoring Sep 22, 2026, 03:26 PM UTC
Status: Monitoring The issue is still present on Azure infrastructure side and ClickHouse Cloud team is actively monitoring for any impact for existing ClickHouse Clusters. Correction on earlier impact description: Provisioning of new instances is expected to work. Operations like autoscaling of the ClickHouse Keeper replicas can be stuck or slow. Latency for insert and DDL queries are not affected, thanks to cross-AZ redundancy. Affected components germanywestcentral (Degraded performance)
- monitoring Sep 22, 2026, 05:02 PM UTC
Status: Monitoring Azure support shared they are working on fixing the underlying issue, we started seeing some recovery but the incident is not completely resolved yet. We are working with Azure to get this fixed as soon as possible. Affected components germanywestcentral (Degraded performance)
- resolved Sep 22, 2026, 06:25 PM UTC
Status: Resolved The underlying AZ has recovered and we are fully back online. Affected components eastus2 (Operational) germanywestcentral (Operational) westus3 (Operational) uaenorth (Private region) (Operational) australiaeast (Private region) (Operational) japaneast (Private region) (Operational)