Dashboard storage use—which section should I believe?

[DavidHertzberg]

For several weeks I've noticed a discrepancy between storage use reported for multi-drive-backup days in the Backups section vs. the Storage section of my Retrospect 12 Dashboard. Unless someone can provide a good reason for the discrepancy, I'm going to report it as a bug.

 

 

As all you attentive readers must know by now, on Saturdays I do a Recycle Media Set backup of all 6 of my hard drives, rotating among 3 Media Sets. Yesterday I backed up onto Media Set Blue. The total to the left of the Sat. bar graph of the Dashboard's Backup section reported I had backed up 181.2GB, which agreed with the sum of the subdivision mouse-overs in the bar graph, and these in turn agreed with the Log. However the total to the left of the bar graph for Media Set Blue in the Storage section of the Dashboard reported that I had Used 200GB. The difference, allowing for the fact that the Storage section totals round (upwards?) to an integer, is about 18.8 GB. That seems to be rather close to the 17.8GB Log difference between 48.2GB found and 30.4GB copied for "Macintosh HD New" on "Ronny's Mac Pro" server, which is no doubt due to deduplication because both that drive and "Macintosh HD" on "David's MacBook Pro"—which backs up first on Saturday—are running OS X 10.10.5 ("Macintosh HD" on "Ronny's Mac Pro" runs OS X 10.6.8 when it boots, "Macintosh HD OS X" on "Mimi's Old G4" runs OS X 10.3.9, and the other two drives on "Mimi's Old G4" run OS 9.1 when they boot).

 

 

The Storage section totals may include Snapshots, which—per the Log—the Backup section totals do not; subtracting those would bring the Dashboard section discrepancy even closer to the Log found/copied difference for "Macintosh HD New". If you were thinking "Media Set drive catalog", think again; the Finder's GetInfo total for 1-Media Set Blue is 215GB. FYI, Media Set Blue is a Disk Media Set.

 

Can anyone explain the discrepancy?

[DavidHertzberg]

A week later nobody has attempted to explain it, so I've re-posted it as a bug.

 

 

As further evidence, I ran my Saturday Recycle Media Set backup again yesterday—this week onto Media Set Red. I got the same 18GB difference between the total to the left of the Sat. bar graph of the Dashboard's Backup section and the total to the left of the bar graph for Media Set Red in the Storage section. Media Set Red is also, FYI, a Disk Media Set.

 

 

Here's my shot at an explanation of what is really a "conceptual" bug. It kind of makes sense to have the un-deduplicated "found" total for a drive be shown in _one_ place on the console, to reassure users that in fact all of the contents of a particular drive has been backed up _someplace_ on the Media Set. But that place should be the total to the left of the day's bar graph of the Dashboard's _Backup_ section, and also in the subdivision mouse-overs in the day's bar graph. The total to the left of the bar graph for the Media Set in the _Storage_ section of the Dashboard should be a sum of deduplicated "copied" totals, because that section is for users concerned about storage use.