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Accepted
James Simpson
Asked: 2017-01-03 06:44:21 +0800 CST

Mongod stuck in stop/waiting on Ubuntu 14.04

  • 772

I installed MongoDB on Ubuntu 14.04 as per the documentation. It runs and works fine, except that it mysteriously stops every few hours and requires a manual restart with service mongod restart to get going again. There's nothing in the mongod.log when this happens.

In addition, when I restart and then check status with service mongod status, it gives me mongod stop/waiting event hough the application is able to connect to it. I've been searching around on how to debug this, but am stuck at this point.

ubuntu mongodb ubuntu-14.04 upstart

2 Answers

  1. Best Answer

    It turns out the issue was with OOMkiller killing the mongod process. As noted in the MongoDB production notes (https://docs.mongodb.com/v3.2/administration/production-notes/#disk-and-storage-systems):

    Allocating swap space can avoid issues with memory contention and can prevent the OOM Killer on Linux systems from killing mongod.

    I used the below commands to create the swap file, which fixed the issue (on Ubuntu 14.04):

    > sudo fallocate -l 2G /swapfile
> sudo chmod 600 /swapfile
> sudo mkswap /swapfile
> sudo swapon /swapfile

    I then added the following to the /etc/fstab file to make this permanent:

    /swapfile none swap sw 0 0

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  2. You need to first uninstall the mongodb, you can use:

    sudo apt-get purge mongodb-org*

    After this, install mongodb by

    sudo apt-get install mongodb

    And then update:

    sudo apt-get update

    You are done with the installation of mongodb. You can check it by using the below command:

    mongo --version
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