In large restorations, index builds can take a long time. When this happens, currently mongorestore offers no progress or other indicator that “all is well”.

Two ideas to assuage this:

1. Copy mongomirror’s LogIndexBuildProgress() function over, and run it every 10m or so.
2. In that same interval, suggest increasing the server’s maxIndexBuildMemoryUsageMegabytes.

… or, we could do both. (Or maybe something even better?)