Force sparse MongoDB data files.
And reduce the size of namespace files.
Instructions
Run make install.
This patches a version of the Meteor tool so that it runs the MongoDB server differently.
Check what version it patches in the Makefile.
You can use make uninstall to go back to stock.
Force sparse data files
MongoDB doesn't preallocate its data files when it runs on NFS.
We simulate this condition with a shim over the fstatfs64 function, implemented in nfslie.c.
This probably leads to instability if you later run out of disk space that MongoDB thinks you should have.
Reduce the size of namespace files
Each collection and index counts as a namespace. ... The default value of 16 megabytes provides for approximately 24,000 namespaces.
We reduce it to 1 MB. Now you can only have like 1,500 namespaces. You're really gonna have to tighten your belt to build an app under that constraint.
Disable journaling
Note: I haven't seen this in the latest version of stock, so I didn't include it in the patch this time. Journal files take like 384 MB right off the bat, in a blank app. Only you can rationalize forgoing this durability.