Introduction

This document serves as a Root Cause Analysis for the Primo service interruption experienced by Ex Libris customers on April 30th and May 1st, 2018.

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 Primo MT APAC01 instance at the APAC Data Center during the following hours: 

April 30^th, 2018 from 9:43 AM until 10:47 AM Singapore time
During the event, the service was available but slow for the environment

May 1st, 2018 from 3:48 PM until 8:44 PM Singapore time.
During the event, there were short periodic of system disruption

Root Cause Analysis

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

As part of the investigation of April 30th disrupton, Ex Libris developers took memory dump on May 1st that caused the service disruption on that day.
Following deep investigation, it was found that a software malfunction in the area of timeout management lead to a chain reaction, where when a single search node  was slow the others hang.

Technical Action Items and Preventive Measures

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

• A fix to the malfunction was created and currently being tested.
  It is planned to deploy it as part of May release.

Customer Communication

May 7th session

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: http://status.exlibrisgroup.com/