Sierra ; Polaris DC01 - RCA - June 16, 2026

Introduction

This document serves as a Root Cause Analysis for the service interruption experienced by Sierra and Polaris customers–hosted in DC01 (Seattle Data Center).

The goal of this document is to share our findings regarding the event, specify the root cause analysis, outline actions to be taken to solve the downtime event, as well as preventive measures Clarivate is taking to avoid similar cases in future.

Event Timeline

Service interruption was experienced across multiple products hosted in DC01 during the following timeframe:

June 16, 2026, from 02:09 PM until 10:19 PM PDT.

During the event, some systems were unavailable for all or part of this timeframe, with services restored incrementally as systems recovered.

Root Cause Analysis

Clarivate Engineers investigated this event to determine the root cause analysis with the following results:

The incident was caused by a disruption in the data center storage layer, which affected access to shared storage. As a result, many servers entered a read-only state, leading to broad service unavailability and degraded performance across Sierra and Polaris environments.

After the storage service was stabilized in coordination with the storage vendor, our engineering teams carried out recovery actions, including DNS restoration and staged server reboots, which gradually restored full-service availability. We are also continuing to work closely with the vendor to identify the underlying issue in the storage layer that led to the incident.

Technical Action Items and Preventive Measures

Clarivate has taken the following actions and preventive measures to avoid such an occurrence in future:

Migrate all critical infrastructure services such as DNS to local disk storage to ensure availability during storage disruptions.
Expand and standardize automated recovery mechanisms (including read-only detection and reboot automation) across all platforms, including both Linux and Windows environments.
Enhance monitoring capabilities to explicitly detect read-only file system state.

Customer Communication

Innovative is committed to providing customers with prompt and ongoing updates during Cloud events. Ongoing and prompt updates on service interruptions appear in the system status portal at this address:http://status.exlibrisgroup.com/

These updates are automatically sent as emails to registered customers