Is your MongoDB properly running? A simple way to check it would be with:
service mongod status
On my CentOS 5.x it gave:
mongod dead but subsys locked
There are two possible causes I could find. First is related to disk space. If you do not have enough space for dbpath (database directory) then you may get this message.
mongod --config mongod.conf
For MongoDB 3.x (latest version)
storage: mmapv1: smallFiles: true
For version 2.6+
storage: smallFiles: true
For version 2.4 and less
smallfiles = true
Then just execute mongod to accept your config file (here it assumes that location of the config is /etc/mongodb.conf):
mongod -f /etc/mongodb.conf
Documentation for smallfiles parameter:
Set to true to modify MongoDB to use a smaller default data file size. Specifically, smallfiles reduces the initial size for data files and limits them to 512 megabytes. The smallfiles setting also reduces the size of each journal files from 1 gigabyte to 128 megabytes.
Alternatively you can run mongod with --smallfiles parameter like: mongod --smallfiles
On my machine the problem was different. It was expecting a directory /var/lib/mongod with proper permissions, which was not there. The solution is simple:
sudo mkdir /var/lib/mongod sudo chown -R mongod /var/lib/mongod
However how did I find out about the problem(s) in the first place. Again the solution is very simple. I looked in the log file:
Always start with the log file.
Finally you can verify that your system is running properly with:
sudo service mongod status
After fixing it gave:
mongod (pid 26194) is running...
Now that’s solved, let’s get back to mongodb coding..