MongoDB Upgrade to version 8.0

Other MongoDB Topics MongoDB Server Development
1

Hello Everyone,

Recently I have upgraded MongoDB Community Database from v6.0 to v8.0. And since when I login into mongo shell I am getting two warnings.

  1. For customers running the current memory allocator, we suggest changing the contents of the following sysfsFile
  2. We suggest setting the contents of sysfsFile to 0.

image

Server Details :
OS Version: RHEL 8.10
MongoDB Version Upgrade: v6.0.19 to v8.0.6 (PSS Replication Cluster)
FCV Value is still 7.0.

What does these warning indicates? and what OS values needs to be updated?
I can’t find related details on MongoDB official documentaion.

2

Hi @Vishal_Ghodake

With 8.0 there is a change in memory allocator. The recommended OS setting have changed to support this.

This page give the settings and example systemd unit to set it up.

ref:
https://www.mongodb.com/docs/manual/administration/tcmalloc-performance/

2 Likes
3

hi Chris,

Thank You for the advice.

As per my understanding, below are the only settings different in MongoDB 8.0 than earlier versions.

In MongoDB v7.0:

  1. /sys/kernel/mm/transparent_hugepage/enabled: never
  2. /sys/kernel/mm/transparent_hugepage/defrag: never

In MongoDB v8.0:

  1. /sys/kernel/mm/transparent_hugepage/enabled: always
  2. /sys/kernel/mm/transparent_hugepage/defrag: defer+madvise
  3. /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none: 0
  4. /proc/sys/vm/overcommit_memory: 1

Please help me if there are any other changes required.