A superpower of doing Time Machine backups to a Synology is that you can put it on a BTRFS drive with automatic snapshotting. About once a year something seems to happen that causes Time Machine to give a “whoopsie, gotta start over from the beginning again!” sort of error. I’ve found that going back a day or two with snapshots on BTRFS fixes the problem.

For me it was more like every day. I gave up on Time Machine very quickly.

The underlying problem is that Time Machine stores a disk image over the network[0]. If the disk image is not unmounted cleanly, Time Machine treats it as horribly corrupted and refuses to touch it. And this happens very often if you're using a laptop that will be unexpectedly disconnected from its storage constantly.

[0] This is to support things like hardlinks, etc. Ironically this is to emulate what BTRFS snapshots do natively. No clue if modern Time Machine uses APFS, but so long as they shove the actual data inside of a disk image this problem will continue occurring.

I've given up on it and bought a SSD to do local backups. My new plan for the Synology is to get Minio running on it and then use Arq Backup to send the data.

Update: This is working quite well. I occasionally run into errors "Error: The network connection was lost." but I think this is mostly because of my Wifi.

> About once a year something seems to happen that causes Time Machine to give a “whoopsie, gotta start over from the beginning again!” sort of error.

This is true. Though I've had very good luck re: ZFS and my current Samba config.

If you're not already, you should be snapshotting before and after each network mount. See: https://kimono-koans.github.io/opinionated-guide/#on-network...

Yh, and even they can't get it right. You lose connectivity once in a while and the only way to recover is to erase the backup and start over.

I came here to see if someone had built a macos native time machine, but this looks like just another hack.

Just posted this in another comment as well. Ditch Time Machine altogether. Use Carbon Copy Cloner instead. It backs up straight to a network drive. Been using it with my Synology for years. Using Time Machine is playing russian roulette with backup data.

In the pre-APFS days, there was one difference in that using time machine would give you snapshots whereas CCC would only be a "dest like source" backup (safetynet would preserve deleted files, but not version modified ones). You could work around this with ZFS snapshots on the destination, but since it's not natively supported it's all a bit clunky. With APFS you get snapshots too, so the only real difference is the UI for restoring a snapshot.

I do wish Apple would allow 3rd party applications to populate "versions", so the inbuilt UI could be used with other apps. It could even fit with their existing Finder extensions: it could bring together different versions of a file on cloud providers, local backups, etc., and present them in a unified UI.

Something happened around Big Sur that made Synology and Time Machine not get along for me. I set the share up with a quota and everything is great and happy. Time Machine backs up. But once that quota is exceeded, Time Machine complains about not having enough free space and quits. It used to delete old backups but now, no matter what I do, it just complains about free space and quits. :(

Yes, you're right. There was a time around Big Sur where it didn't work. It did eventually start working again after some unmentioned fixes from Apple. I skipped Catalina and went straight to Monterey and it's been still fine. I'll be slipping Ventura and going straight to Sonoma.

It’s really weird. The Mac is great, the Synology is amazing. They appear to hate each other.