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    Summon - RCA - February 13, 2020


    This document serves as a Root Cause Analysis for the Summon service interruption experienced by Ex Libris customers on February 13th, 2020

    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 interruption was experienced by Ex Libris customers served by the Summon instance at the North America Data Center during the following hours: 

    February 13th, 2020 from 4:25 PM until 4:50 PM CST Time.

    During the event the service was unavailable.

    Root Cause Analysis

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

    • An unexpected growth in the rights data led to growth of a custom cache used by the CDI Search API layer.  The cache growth hit an OS limit in how the files are stored on disk and a corruption of the cache. This corrupt cache was loaded into the system and led to a system down event. 

    Technical Action Items and Preventive Measures

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

    • On the day of the event, the corrupt cache was quickly diagnosed.  An older cached was put in place and the systems were brought back online.  Applications that generate the cache were paused until the root issue could be fixed.

    • On February 14, a fix to the cache building application was released that allows the system to build correctly with the increased scaling requirements.  All automation was reenabled.


    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:

    Publication History

    Date Publication History
    February 25, 2020 Initial Publication



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