I'm supporting a legacy C++ app that has used structured storage via the COM IStorage class for several years.
We've got a performance problem that shows up when individual streams get larger than around 256MB. Saving changes normally takes just a few minutes, but can jump to over several hours with these larger streams.

If I change from STGM_TRANSACTED to STGM_DIRECT, I get fast performance, but I don't want to lose any reliability.
I suspect that given our usage, (the structured files are normally closed, opened in transacted read/write mode for single user, and committed and released immediately after updating a stream), the transacted mode doesn't actually help reliability. However, our customers have a high monetary value associated with these files, so I need to be sure before
recommending this change.

I also have a question about whether there's a way to determine if a commit with STGC_CONSOLIDATE will
reduce a file's size. I've implemented a consolidate operation, but it takes several hours to complete for files
which contain large streams, even if the file has already been consolidated.

Searching for Structured Storage in the forums comes up with scattered questions, (mostly re how to make it work in a specific language) over a wide variety of forums.

Which forum would be most appropriate for my questions?

Thanks!
- Bruce Hill