CCC backup smaller than it should be?

[sine-nomine]

I've been using CCC for years, but somehow I've only just now noticed that Get Info shows all three of my backups are about 780GB, while my backed-up hard drive is about 920GB. In all cases, "Backup Everything" was selected in the drop-down menu. Maybe I'm missing the obvious, but what's causing the discrepancy in these sizes? Thanks!

 

[maflynn]

Maybe CCC is ignoring the cache folders, swap files, and other temporary type files/objects.

 

[sine-nomine]

That's my hope, but I'm surprised at suck a massive difference in size! (Btw, Time Machine has been disabled for months, so local backups shouldn't still be there, right?)

 

[musique]

You might ask assistance from Bombich (the company that produces CCC). I’ve found them to respond quickly and to be helpful whenever I’ve had questions. Good luck.

 

[Fishrrman]

Have you tried booting from one of your CCC backups, and then "taking a look around" to assure yourself that "everything is there" ... ???

 

[sine-nomine]

I have. Everything seems to be there, and oddly enough Get Info shows about 920GB used when I boot from a backup drive.

 

[maflynn]

Its probably the difference in how OS X computes a gigabyte and how the application does. If you remember, apple changed what constituted a gigabyte a couple of versions ago
1 GB = 1000000000 bytes vs 1 GiB = 1073741824 bytes

 

[sine-nomine]

Hmm, that doesn't seem capable of causing a 140GB discrepancy, though. Plus I'm using Get Info in OS X to determine the sizes of both the source and backup volumes.

 

[Weaselboy]

That's my hope, but I'm surprised at suck a massive difference in size! (Btw, Time Machine has been disabled for months, so local backups shouldn't still be there, right?)

They should not, but sometimes they get stuck. Run the command below in Terminal to see if there is anything hanging around from TM local snapshots.

CCC does not copy caches and swap etc., but I can't see that accounting for the large difference you are noticing.

sudo du -hs /.MobileBackups

 

[MacInMotion]

Bombich (creator of CCC) has some articles explaining some of this:

• The disk usage on the destination doesn't match the source — did CCC miss some files?
• Some files and folders are automatically excluded from a backup task

In your case the big difference is probably from CCC not copying over your Trash. Other big things not copied over are your sleepimage (can be as big as your total RAM), swapfiles (can be even bigger), Spotlight indexes, and local auto-backups.