This document serves as a Root Cause Analysis for the Alma service interruption experienced by Ex Libris customers on January 10, 2021.
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.
Service interruption was experienced by Ex Libris customers served by the Alma NA04 instance during the following hours:
January 10, 2021 from 12:00 AM until 15:43 PM PST: During the event, the services were intermittent except 62 minutes where the service was completely unavailable.
January 16, 2021 from 10:15 AM until 11:26 PM PST: During the event, the services were intermittent.
Root Cause Analysis
Ex Libris engineers investigated this event to determine the root cause of this issue and concluded the following:
During a planned activity on the environment an applicative process went out of sync which caused an excessive load on the database and resulted in a service disruption.
Ex Libris engineers found that the reason for the load was a misalignment in the DB partitions.
The process was stopped during the event, resynced and the system recovered.
The alignment of the DB partitions was performed on January 16th which caused another 71 min of intermittent service after which the system recovered and the misalignment was fixed for good
Technical Action Items and Preventive Measures
Ex Libris has taken the following action and preventive measures to avoid such an occurrence in future:
The applicative process that was running is being reevaluated to ensure stability and to prevent reoccurrence in the future.
Specific monitoring for misalignment in the DB partitions is being developed.
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/
These updates are automatically sent as emails to registered customers.