When doing a rollback, there is no indication of progress in the logs at all - it is difficult to determine whether the rollback is just slow or, potentially, broken. A progress indication, perhaps something like this:

[log time stamp] [rsBackgroundSync] X operations processed (out of total, if known or perhaps a delta from the common point)

Print this every 60 seconds to at least give evidence that something is happening. This should be visible at the default log level