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    Summon Uptime Report - Q1 2020

    Uptime Quarterly Reports are published each quarter to provide a comprehensive view of our uptime performance as measured over the last three (3) months and over the last twelve (12) months. The report measures our performance as defined in the Service Level Agreement.


    This document details the uptime report for the Summon in North America.


    The uptime measured on a rolling 12 month basis April 2019 - March 2020 is 99.98%

    The uptime measured on a rolling 3 month basis January 2020  - March 2020 is 99.94%


    Please note our System Uptime Status page, which allows our customers to view the current status of their instance/environment at any time, using the following link:



    Unscheduled downtime incidents in Q1 2020


    Start time


    End time




    February 11, 2020 01:07 PM 01:42 PM 32
    • An upgraded Solr client library introduced with the Solr 7 search engine has different behavior than the older version previously being used.  The new library requires connections to be explicitly closed where this was not required before.  Connections were not being closed properly on a status check call that is made to the system, leading to a slow build up of stuck threads and allocated memory.
    • As threads increased, the search API eventually became unresponsive leading to a system down event.
    February 12, 2020  10:37 AM 10:47 AM 10 The CDI Search API, now used by Summon, experienced an unexpected memory growth in a cache system due to growth in rights by combined Primo and Summon users.  This increase in memory led to the Search API becoming unresponsive and a system down event.
    February 13, 2020 04:25 PM  04:50 PM  25 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. 
    February 25, 2020  04:00 PM 04:28 PM 28 An invalid real-time availability configuration was committed to production leading to the API layer failing while trying to parse the value.  This failure led to a system wide disruption and search failures.

    Scheduled downtimes during maintenance windows in Q1 2020

    Start Date

    Start Time


    End Time


    Duration (Minutes)



    Total unscheduled downtime minutes during past 12 months


    Total unscheduled downtime in Quarter (minutes)

    Q2 2019 20
    Q3 2019 62
    Q4 2019 0
    Q1 2020 95


    How is Uptime Calculated?

    The uptime calculation is based on the following calculation (as defined in the Service Level Agreement):

    "Uptime" means the total period in minutes during which the Service is available for access and use during this period.


    Uptime Percentage” means Uptime expressed as a percentage, calculated in accordance with the following formula:   


     Uptime Percentage = X /(Y–Z) × 100    


      X = Uptime

      Y = Last 12 months period

      Z = The duration (in minutes) of any SLA Exclusions* during these 12 months


    *SLA exclusions are defined in the contract SLA (e.g. Scheduled maintenance, etc.)


    Further Information

    If you have any queries on the information within this report please contact Ex Libris through your usual channel.

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