Understanding the MongoDB Architecture and Processes - MongoDB High Availability - page 16

Understanding mongosniff
The mongosniff is a tool that is used to fetch live MongoDB collection statistics. While
inserting or querying data from the MongoDB instances, you can run the mongosniff
command and connect it to your MongoDB instance to see what the database does.
Note
Please note that in order to use this utility, you should install the libpcap library first. To
install the libpcap library, please visit its official website at http://www.tcpdump.org/
#documentation .
A simple usage of the mongosniff tool is as follows:
sudo mongosniff --source NET lo0
The preceding command line will listen to the loopback interface (localhost). This interface
is lo0 in Mac OS systems and lo for other operating systems, usually. You can get the list
for your network interfaces using the ifconfig command. If you're using Windows as
the operating system, you can get the list of network interfaces using the following com-
mand:
ipconfig /all
Utilizing mongoperf
The mongoperf tool represents the disk I/O performance. It checks the I/O in a specified
interval and illustrates it. This utility can be used independent of MongoDB.