Linux – mongod fork vs nohup

linuxmongodb

I'm currently writing process management software. One package we use is mongo.

Is there any difference between launching mongo with

mongod --fork --logpath=/my/path/mongo.log --logappend

and

nohup mongod >> /my/path/mongo.log 2>&1 < /dev/null &

?

My first thought was that –fork could spawn more processes and/or threads, and I was suggested that –fork could be useful for changing the effective user (downgrading privileges). But we run all under the same user (process manager and mongod), so is there any other difference?

Thank you

Best Answer

The difference is that with

mongod --fork --logpath=/my/path/mongo.log

Mongo itself forks the process so it can run as a deamon. This is the intended way because mongo might probably do something before forking the new process.

With 

nohup mongod >> /my/path/mongo.log 2>&1 < /dev/null &

Mongo does not know it is forked.

I'd say it is always better to let server software do the forking so it can make optimizations. NoHUP is just for software that does not have a forking option.

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