A YAML config file containing the following info is not accepted by the server.
operationProfiling:
mode: 1
The documentation online says the value should be an int. However starting the server with this config file throws the error
2014-07-13T23:55:33.896+0530 SEVERE: Failed global initialization: BadValue operationProfiling.mode must be a string of the format: (off/slowOp/all)
Modifying the config file to read
operationProfiling:
mode: slowOp
fixes the issue.