Mongodb – Issue with MongoDB Replication Set

Under Windows, in a worst case scenario, your pagefile size might have to be set to the size of your data files + physical memory size. So if your data files take up 50GB on disk, the rough guidance, in your case, is to set pagefile size to 53.5GB. This will improve with MongoDB 2.8 release since the new storage engine does not rely on virtual memory services provided by the OS. On a related subject, your memory size of 3.5GB sounds very low. Take a look at the Hard Page Faults per second under the Resource Monitor -- if the number is in hundreds, you need to dramatically increase your memory size

First of all when you run mongod as a normal user you need to make sure that the particular user has the following permissions:

1. Access to network interface ( open socket ) in order to be able to listen to connections
2. Access to the database folder. The default is accessible only by root or mongod user (/data/db)
3. Access to logging folder /var/log/mongod

All of the above are automatically set and granted for the user mongodb (mongod in earlier versions). If you take a look at /etc/init.d/mongodb you will see that the service will be stared under the user mongodb DAEMONUSER=${DAEMONUSER:-mongodb} and not as root.