We used a Mac Pro running server app as time machine target. The Mac Pro is on a different subnet, so we had to add it as a time machine target via command line:
sudo tmutil setdestination -ap afp://firstname.lastname@example.org/timemachine
This worked pretty well on several machines. Today, I upgraded the Mac Pro from OS X 10.10 and Server 5.0 to macOS 10.13 and Server 5.6. This means, the time machine target stuff was moved from the server into the operating system. I checked the sharing settings:
System Preferences -> Sharing -> File Sharing -> timemachine, rightclick -> Advanced options:
Share over "SMB and AFP"
Share as Time Machine backup destination checked
Next thing I tried was a TM backup on my local machine. Failed with error The network backup disk does not support the required capabilities. My first idea was to resetup my local Time Machine. I thus removed the TM-target and tried to readd it:
sudo tmutil setdestination -ap afp://email@example.com/timemachine Password: Destination password: Disk does not support Time Machine backups. (error 45) The backup destination could not be added.
Same result with SMB instead of AFP.
Then I tried to run a backup on a different machine, same error as above. This machine still has the Mac Pro as a TM target as I didn't remove it yet.
I checked the logs on my local machine and found that TM is trying to use
/Volume/timemachine-4 as target.
mount told me that there are several mounts to the Mac Pro, thus I unmounted everything and restarted my local machine. After that I was at least able to readd te Mac Pro as TM target (via AFP). But a backup resulted in the same error again: The network backup disk does not support the required capabilities.
Does anyone know which required capabilities are not provided (anymore)? Or do I need to open additional ports in the firewall between the two subnets?
After trying this and that, I again removed the TM target, but can't readd it, even after a reboot. However, the log tells me (when trying to mount via AFP):
kernel: (afpfs) AFP_VFS afpfs_vnop_ioctl: SyncDir failed 22 backupd: (TimeMachine) [com.apple.TimeMachine:TMLogError] Mountpoint /Volumes/timemachine does not support required Time Machine capabilities!
But I also see (besides some other NetAuthSysAgent messages)
(AppleShareClientCore) ERROR: AFP_OpenSession - Login failed with 80
Don't know whether this indicates a problem or is normal operations, e.g. due to falling back to some other authentication.
The target share point on the Mac Pro is on a Thunderbolt attached Lacie device, which is still on the old Mac OS Extended (Journaled) file system. Could this be the problem?