Mongo Is Not Available - Fluid Topics - 3.8

Fluid Topics Troubleshooting Guide

Product
Fluid Topics
FT_Version
3.8
Platform
RHEL
Category
Reference Guide
language
English

Issue

The Fluid Topics portal displays the following error message(s):

  • 500 — Internal Server Error

The Back Office displays the following error message(s):

  • "Mongo is not available"

Fluid Topics PaF ended in the following status:

  • TERMINATED (crashed)

Impact(s) on users

If back-end and front-end Mongo databases are not mutualized:

  • This issue prevents KHUB Admin users from uploading content to the portal or managing sources.
  • This issue causes no impact to end-users.

If back-end and front-end Mongo are mutualized:

  • The Fluid Topics portal is not available and displays a 500 error.
  • This issue prevents KHUB Admin users from uploading content to the portal or managing sources.

Possible root cause(s)

This issue might occur when:

  • MongoDB has been oomkilled because Fluid Topics PaF was using up all memory available.
  • MongoDB cache memory configuration exceeded server available memory.

Solution(s)

This issue should be fixed in AFS v7.9.

On the server(s) hosting the front environment, increase or decrease the cacheSize parameter in the /etc/mongod.conf file according to your specifics.

By default, this value is set to 10 Gb and can be turned into 4 Gb to save memory, but performance issues may ensue.

To prevent this issue from happening:

Check Fluid Topics failing PaF configuration to ensure that the following option are properly configured:

  • The disableStem option of the thesaurus parameter (all existing thesauri (Back-Office vocabularies) must be listed in the Fluid Topics PaF configuration and not disabled).