MongoDB Replica set is ALWAYS 100% RAM

Even I put this to 16gb ram, it goes to 100%

Any one have some insight?

Are you running all of the replica set members on 1 computer? How many members do you have? Are you using wiredtiger?

Virtual memory size and resident size will appear to be very large for the mongod process. This is benign: virtual memory space will be just larger than the size of the datafiles open and mapped; resident size will vary depending on the amount of memory not used by other processes on the machine.

from here, not sure if relevant,


Yeah I think this is nothing to worry about.
On my Nodechef servers all my mongoDB instances run at 90-100% RAM utilisation when in use.
I think the process just keeps as much in RAM as the system allows for speed.

Just to close the question, it seems this is OK.

I’ve been runnin 48 hours now with NO performance issues. Microsoft servers do this too. My job has a server that new relic reports at 100% at all times.