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    European Data Center- RCA - October 16, 2019


    This document serves as a Root Cause Analysis for the service interruption experienced by Ex Libris customers.
    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 Ex Libris is taking to avoid similar cases in future.

    Event Timeline

    Service degradation was experienced by Ex Libris customers located in the Amsterdam Data Center during the following hours:

    October 16, 2019 from 01:31 PM until 01:59 PM Amsterdam time

    During the event, the environment encountered network access instability, no data was impacted

    Root Cause Analysis

    Ex Libris Engineers investigated this event to determine the root cause with the following results:

    An unexpected CPU spike on the Web Application Firewall (WAF) caused a high Network connections queue on one of the Load Balancers which caused interference to the datacenter Network connectivity. This was resolved after reducing the high CPU load.

    Technical Action Items and Preventive Measures

    Ex Libris has taken the following action and preventive measures to avoid such an occurrence in future:


    • Ex Libris engineers re-balanced between the Load Balancers for an additional redundancy.
    • Ex Libris engineers added an additional monitoring level check.
    • Ex Libris engineers are working with the vendor support, to understand the sudden high CPU spike.



    Customer Communication

    ExLibris 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:

    These updates are automatically sent as emails to registered customers.

    Publication History

    Date Publication History
    October 23, 2019 Initial Publication



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