Open Radar

 
Summary:
My time machine is making a full backup for no good reason at all every single time. It links 0 items and backup logs always show that  supposedly every file needs backup. But tmutil compare shows the correct amount of changes. It is making a deep traversal every single time. I attached a sample syslog extract during such a backup as a reference.

What I want is to try to lay out what I tried and hopefully have some engineer notice it, say it’s an edge case or fix it (you can call me if that helps - #number - I am fluent in English) so no other person hits that, as this situation is rather frustrating. I included everything I tried so far in the Notes section.

If it should turn out that you see that it is related to me using openzfsonosx, please, please tell me what’s causing it so I can file a github bug and work with ilovezfs and lundman to get it fixed!

Steps to Reproduce:
It all started with me deleting the unnamed 263 Byte file on „/„, which turned out to be a mobile time machine created UUID thing. I have no idea why I see it in Finder (I don’t show invisible stuff) and I can delete it but it gets recreated when I switch on time machine or rather specifically the mobile time machine component. 

Expected Results:
Time machine should, as tmutil compare shows, correctly link previous stuff and transfer incremental stuff and not fully backup every single time.

Actual Results:
Time machine makes a full backup every single time.

Regression:
I noticed the unnamed file on previous versions but never ran into the problem of having always full backups. This is new in 10.11

Notes:
Here is a rundown of what i tried so far (as also publicly documented in https://discussions.apple.com/thread/7399904:

What I tried so far:
 
- every single trick from pondini.org's http://pondini.org/TM/D7.html (every backup is a full backup...). The thing is, it doesn't depend on what I exclude, I can include everything so only 300MB of /usr/local etc are backed up and still it's a full backup every single time
- I tried doing inherit backups, associate disks etc (I didn't change my system at all)
- I tried running it to a fresh external hard drive
- I tried running it to a network time machine destination
- I tried booting into safe mode
- I tried deleting .fsevents and .dbfsevents on the Fusion volume in question
- I tried installing OS X over it (an install on top of the existing one)
- I tried running a backup from a clone
- I tried disabling/enabling local time machine snapshots
- I tried checking my startup volume with disk utility and even rebuilt the B-Tree with fsck-hfs -Race
- Look into a SMART Monitoring tool, but both of the disks (source is a Fusion drive) work as expected
- I looked into the created backups with TimeTracker to confirm these were really full backups, and yes, they were
- I tried running the backup to an unencrypted destination disk
- Deleting a specific folder in /var/folders as described in https://discussions.apple.com/message/29551937#29551937

If you have any idea what is going on - especially why tmutil compare shows a correct amount of changes and then running a backup doesn’t seem to get the info, please help me.