Sierra ; Polaris DC04 - RCA - August 9, 2026

Introduction

This document serves as a Root Cause Analysis for the service interruption experienced by Sierra and Polaris customers–hosted in DC04 (Chicago 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 by the single-tenant Sierra and Polaris environments hosted in Clarivate's Chicago Data Center on:

August 9, 2026, from 05:52 AM CDT until 12:41 PM CDT.

During this window, affected customers were unable to access their Sierra and Polaris environments.

While the total engineering resolution window spanned several hours, the operational impact varied significantly across the customer base. Most systems experienced a brief service interruption of 30 minutes or less, with many recovering automatically before the disruption was noted.

A subset of environments required a more complex recovery. These systems, upon reboot, necessitated manual intervention by our Support and engineering teams to fully restore all functionalities.

 

Root Cause Analysis

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

Customers experienced a loss of access to their Sierra and Polaris environments as multiple servers became temporarily unreachable. On investigation, we identified that a number of environments had entered a protective read-only state that prevented normal operation. Our engineers acted with urgency, restarting the affected servers and progressively restoring all impacted applications and environments to full service.

Initial analysis points to an internal storage component that entered an unexpected read-only condition. A detailed investigation by our infrastructure partner has identified the underlying cause, and a corresponding fix has been developed. This fix will be applied as part of an upcoming upgrade to the affected component.

Technical Action Items and Preventive Measures

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

  • We are collaborating closely with our infrastructure partner to resolve any remaining technical obstacles and deploy the identified fix, including the associated component upgrade, at the earliest opportunity.

  • We are accelerating recovery times by improving restart automation and streamlining internal application startup processes.

Customer Communication

Clarivate 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.