Primo MT APAC01 - RCA - May 6, 2020

Introduction

This document serves as a Root Cause Analysis for the Primo service interruption experienced by Ex Libris customers on May 6, 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 Primo MT APAC01 instance at the APAC Data Center during the following hours: 

May 6th, 2020 from 11:41 AM until 2:17 PM Singapore time

During the event, the service was unavailable for the environment.

Root Cause Analysis

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

During a scheduled maintenance to Primo Central that included a software update, the Singapore Data Center traffic failed to switch to the active Primo Central system.
This started causing lack of Primo Central results until the Primo Central SP installation finished.
Due to the unavailability at that time, the Primo FE's accumulated a significant amount of pending search requests that overloaded the Primo Front end machines and as a result , the local search results were partial.

To solve that, we conducted a full Environment restart – during that the local search results were missing until the process ended successfully.

Technical Action Items and Preventive Measures

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

• Fixed the configuration issue to make sure the connection between Singapore Data Center and Primo Central is always working
• Development will add a stress relief mechanism to better handle cases when an outer service is not responding so the environment will continue to be available for local searches and other functionality.

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: http://status.exlibrisgroup.com/