Time Machine Back Up to Synology NAS

It may fail to restore when needed.

The AFP implementation in a NAS is a re-engineered hack because Apple never licensed it. Many people here reported problems when trying to restore.

There really isn’t any sort of restore anymore as you just reinstall the OS and Migrate from the backup. So, maybe it will work until Apple drops AFP completely.

This doesn't surprised me in one bit! Time Machine was NEVER intended to work outside DAS connection! Sure some users boast they have hack it to work on SMB but the use of two different clock sources screws with SMB! This happens in Windows world Too with SMB! So your errors have to with two direness clock sources between on SMB network between two machines so errors creep Inyo Time Machine! So put both the Synology to it's Time Service and then connect your Mac to same system to fix!

In your Mac in it System Preference->Date&Time, make sure it is using the Time Server as the Synology is using! This way the clock lift won't screw up SMB connections! Yes working in Windows environment we saw the same thing 0n SMB to dumb NAS and the clock lift screw with users SMB!

Surely not every NAS maker's implementation of AFP is the same,

Apple has never licensed their implementation, so the NAS manufacturers must use a hack. Certainly there are not multiple AFP hacks in the wild. That would be an extraordinary amount of work for multiple entities to try to reverse engineer Apple's File Server protocol. I can only imagine they all use the same one, Netatalk. It still seems to be in active development, so perhaps they have fixed the issues that cause the backups to fail. The NAS manufacturer would have to update their firmware to include a version of Netatalk that has corrected the problems.

The only network protocol Apple supports with TM is SMB: Backup disks you can use with Time Machine - Apple Support.

As you and countless others have determined, it will be unreliable with Synology NAS devices. It may also be unreliable with other NAS manufacturers but the only personal experience I have is with Synology. Short story, they refunded my money when I proved it didn't work.

Also, as you and many others have determined, it will appear to work, perhaps for a very long time. When you attempt to restore a backup, it is very likely to fail. Those facts should cause you to conclude a non-Apple NAS is unsuitable for use with Apple's Time Machine software.

As for AFP: Apple released certain technical details regarding its implementation back in the '90s, but they never licensed it to anyone. No one but Apple uses it, because they can't.

For those reasons AFP really isn't a solution, and will be as unreliable and likely fail as SMB.

I know time machine didn’t exist in the 90s, but you said Apple publish the specifications. Did they continue to post updates post OS X? Time Machine over SMB requires conformance to a specifications of the same name, so I assume some things were added to AFP to enable Network backups. Much like Apple’s implementation of SMB, I had no problems backing up

and restoring over a network over AFP.

Maybe time machine worked over both of Apple’s implementations of each protocol because they controlled both implementations.

Anyway, if you’re having this issue on NAS drives and specially Synology drives, what cured it for me was ensuring that AFP is the preferred protocol for file sharing on the NAS. When SMB was selected it failed everytime.

Using the fake AFP on a NAS will appear to successfully create a backup, but when it becomes necessary to recover using that backup, it may fail.

Barney, they do not have to reverse engineer, as Apple published a book on the AFP protocol back in the 80’s or 90’s and released addendum's from time to time.

Although it did help to have a real Apple AFP server to protocol sniff against to make sure your implementation was doing the same thing as Apple’s.

I worked on the Digital Equipment Corporation OpenVMS PATHWORKS for Macintosh product back in the day.

Did they document all the tweaks they made to make it compatible/reliable with Time Machine?

The many problems restoring from a NAS seems to indicate they didn’t. There certainly were some posts with direct-connected drive, but it didn’t seem anywhere near the number of NAS related issues.

Barney,

Time Machine did not exist back in the '90's 😁

Neither did the Unix based Mac OS X. We were still on the Classic Mac OS 7, 8 and 9 at the time.

However, from what I know about Time Machines on-disk layout, the ability to create that already existed in the protocol. The ability to create file system hardlinks, which is most of the magic of original Time Machine, existed back in the 90's although the file system implementation got better on Mac OS X.

While we were working on our product Apple would release via Tech Notes updates to the AFP protocol, and we would have to adapt our OpenVMS based file server to implement them in our PATHWORKS file server. However, around '95 Digital canceled the project, and I went off to the Digital UNIX (aka Tru64 UNIX) group. Digital UNIX was also a MACH based micro kernel, similar to Mac OS X.

Also do not get me wrong. Implementing an AFP file server on another platform, even if you have a copy of the AFP protocol specs is still a non-trivial task, so any vendor that implements and maintains their own AFP file server will most likely use an existing package, such as NetaTalk (or similar) rather than write and maintain their own.

Pathworks. Oh my gawd Bob… 🤓