Mongodb: why is my mongo server using two PID's?

Question

I started my mongo with the following command:

[lucas@ecoinstance]~/node/nodetest2$ sudo mongod --dbpath /home/lucas/node/nodetest2/data
2014-06-07T08:46:30.507+0000 [initandlisten] MongoDB starting : pid=6409 port=27017 dbpat
h=/home/lucas/node/nodetest2/data 64-bit host=ecoinstance
2014-06-07T08:46:30.508+0000 [initandlisten] db version v2.6.1
2014-06-07T08:46:30.508+0000 [initandlisten] git version: 4b95b086d2374bdcfcdf2249272fb55
2c9c726e8
2014-06-07T08:46:30.508+0000 [initandlisten] build info: Linux build14.nj1.10gen.cc 2.6.3
2-431.3.1.el6.x86_64 #1 SMP Fri Jan 3 21:39:27 UTC 2014 x86_64 BOOST_LIB_VERSION=1_49
2014-06-07T08:46:30.509+0000 [initandlisten] allocator: tcmalloc
2014-06-07T08:46:30.509+0000 [initandlisten] options: { storage: { dbPath: "/home/lucas/n
ode/nodetest2/data" } }
2014-06-07T08:46:30.520+0000 [initandlisten] journal dir=/home/lucas/node/nodetest2/data/
journal
2014-06-07T08:46:30.520+0000 [initandlisten] recover : no journal files present, no recov
ery needed
2014-06-07T08:46:30.527+0000 [initandlisten] waiting for connections on port 27017

It appears to be working, as I can execute mongo and access the server. However, here are the process running mongo:

[lucas@ecoinstance]~/node/testSite$ ps aux | grep mongo
root      6540  0.0  0.2  33424  1664 pts/3    S+   08:52   0:00 sudo mongod --dbpath /ho
me/lucas/node/nodetest2/data                                                            
root      6541  0.6  8.6 522140 52512 pts/3    Sl+  08:52   0:00 mongod --dbpath /home/lu
cas/node/nodetest2/data                                                                 
lucas     6554  0.0  0.1   7836   876 pts/4    S+   08:52   0:00 grep mongo

As you can see, there are two PID's for mongo. Before I ran sudo mongod --dbpath /home/lucas/node/nodetest2/data , there were none (besides the grep of course). How did my command spawn two PID's, and should I be concerned? Any suggestions or tips would be great.

Additional Info

In addition, I may have other issues that might suggest a cause. I tried running mongo with --fork --logpath /home/lucas... , but it did not work. More information below:

[lucas@ecoinstance]~/node/nodetest2$ sudo mongod --dbpath /home/lucas/node/nodetest2/data
 --fork --logpath /home/lucas/node/nodetest2/data/                                      
about to fork child process, waiting until server is ready for connections.
forked process: 6578
ERROR: child process failed, exited with error number 1

[lucas@ecoinstance]~/node/nodetest2$ ls -l data/
total 163852
drwxr-xr-x 2 mongodb nogroup     4096 Jun  7 08:54 journal
-rw------- 1 mongodb nogroup 67108864 Jun  7 08:52 local.0
-rw------- 1 mongodb nogroup 16777216 Jun  7 08:52 local.ns
-rwxr-xr-x 1 mongodb nogroup        0 Jun  7 08:54 mongod.lock
-rw------- 1 mongodb nogroup 67108864 Jun  7 02:08 nodetest1.0
-rw------- 1 mongodb nogroup 16777216 Jun  7 02:08 nodetest1.ns

Also, my db path folder is not the original location. It was originally created under the default /var/lib/mongodb/ and moved to my local data folder. This was done after shutting down the server via /etc/init.d/mongod stop .

I have a Debian Wheezy server, if it matters.

Answer 1

Regarding the 2 processes with the mongod in them after using sudo to run mongod, that is normal. That is how sudo runs. The actual mongod process that is running the database and that you are connecting to with mongo is

root 6541 0.6 8.6 522140 52512 pts/3 Sl+ 08:52 0:00 mongod --dbpath /home/lu cas/node/nodetest2/data

You can always check this by looking at the mongod.lock file in your dbpath - in your case it should be in

/home/lucas/node/nodetest2/data

Regarding your attempt to fork and use a logpath, you are setting up logpath incorrectly. It needs to be a file name, not a directory. Something like:

--logpath /var/log/mongodb/mongo.log