How to know when my MongoDB database overhead reaches its limit?

Question

I installed a MongoDB database on my server. My server is in 32Bit and I can't change it soon.

When you use MongoDB in a 32Bit architecture you have a limit of 2,5Go of data, as mentionned in this MongoDB blog post.

The thing is that I have several database. So how can I know if I am close or not to this limit ?

Answer 1

Mongo will start throwing assertions when you hit the limit. If you look at the logs, it will have a bunch of error messages (helpfully) telling you to switch to a 64-bit machine.

Using the mongo shell, you can say:

> use admin
> db.runCommand({listDatabases : 1})

to get a general idea of how close to the limit you are. Sizes are in bytes.