I'm encountering the following error upon executing sudo service mongod start in terminal.

    mongod.service - MongoDB Database Server
   Loaded: loaded (/lib/systemd/system/mongod.service; disabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Thu 2018-10-18 12:43:22 ACDT; 7s ago
     Docs: https://docs.mongodb.org/manual
  Process: 3155 ExecStart=/usr/bin/mongod --config /etc/mongod.conf (code=exited, status=100)
 Main PID: 3155 (code=exited, status=100)
      CPU: 22ms

Oct 18 12:43:22 david- systemd[1]: Started MongoDB Database Server.
Oct 18 12:43:22 david- mongod[3155]: 2018-10-18T12:43:22.736+1030 I CONTROL  [main] Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'
Oct 18 12:43:22 david- systemd[1]: mongod.service: Main process exited, code=exited, status=100/n/a
Oct 18 12:43:22 david- systemd[1]: mongod.service: Unit entered failed state.
Oct 18 12:43:22 david- systemd[1]: mongod.service: Failed with result 'exit-code'.

I am unfamiliar with this error, could anyone please suggest what the fix might be?

2 Answers 2


Fixed using this answer from another post:

Open /etc/mongod.conf and look for dbPath: /xyz/xyz

Use the following command to provide the rights to mongodb

sudo chown -R mongodb:mongodb /xyz/xyz


Check the log file on dbath . This is located normally on /var/log/mongodb The log file is mongodb.log

The problem for me was low space on disk... I had the same issue you have .

I had no empty space on disk so I have used the smallfiles options on the file /etc/mongodb.conf Simply add the line on this configuration file: smallfiles = true

  • I feel so dumb... Oct 1, 2021 at 15:32

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