In his “what I’ve learned while using MongoDB for an year” post, Simon Maynard recommends 5 metrics to always monitor:
- index sizes
- current ops
- index misses
- replication lag
- I/O performance
The 1st and the 3rd are about making sure all your MongoDB working set (including indexes) fits in RAM.
Original title and link: 5 Things to Monitor in MongoDB ( ©myNoSQL)