Presently, we are inconsistent with logging index builds. For example, _id indexes do not log "starting index build" like other indexes do unless they belong to specific collections that use that code path.
Additionally, in some cases it is not sufficient to rely on logs in low-level IndexBuildBlock code to determine index build progress. We have logs on the primary that are outside of low-level IndexBuildBlock code, e.g., registering the build. However, we do not log the beginning of index builds on secondaries. An index build can fail at a variety of points, in some cases before the pertinent logs occur, so it is useful to have additional progress logs available.

1. We should standardize logging of index builds between _id indexes and non-_id indexes.
2. We should ensure that logs exist, possibly at different log levels, early on in index builds on both primaries and secondaries.
3. We should add more information about the collection on which the index build is occurring in our existing logs.