Time Machine not backing up external RAID0 drive

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Level 1

4 points

Time Machine not backing up external RAID0 drive

macOS - Sequoia 15.6
Data Drive - RAID0 consisting of dual Acasis TB5 enclosures called "RAID"
Time Machine backup drive - Synology DS1817+ NAS running DSM 7.2.2-72806 Update 4 (have also tried a locally attached TB4 drive with same result)

Problem: Time Machine doesn't backup anything in the RAID0 except the folder "RAID" (nothing inside the folder.. just the folder).

What I've tried:

Verified the subfolders in "RAID" aren't in the exclusion list
Time Machine has Full Disk Access under both admin and my username.
Using a locally attached external drive (only backs up an empty folder named "RAID")

What am I doing wrong?

Thanks in advance.

Mac Studio

Posted on Aug 16, 2025 08:57 PM

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Answer 1

Rudegar

Level 10

178,848 points

Aug 17, 2025 06:09 AM in response to avikb123

if it was me then I would look for

TimeMachine is not backing up my external drive… : r/mac

Time Machine not backing up external driv… - Apple Community

more

Time Machine not backing up external drive - Googl

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Answer 2

avikb123 Author

Level 1

4 points

Aug 17, 2025 09:06 AM in response to Rudegar

Thanks, I did.

The first link is why I tried the first bullet "Verified the subfolder...."

The second link is why I tried the second bullet "Time Machine has full disk access...."

The third link is what lead me to the first two.

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Answer 3

Aug 17, 2025 09:29 AM in response to avikb123

What are you using to form the stripe-set with those NVMe drives? Apple’s software RAID?

Is the resulting stripe-set formatted APFS? Using a RAID disk for time machine - Apple Community

SoftRAID apparently works: https://software.owc.com/knowledge-base/can-i-use-softraid-with-time-machine/

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Answer 4

avikb123 Author

Level 1

4 points

Aug 17, 2025 11:36 AM in response to MrHoffman

Hi, I'm using Apple's native disk utility and selecting RAID 0 formatted with APFS.

I appreciate the first link, but that seems to be someone using time machine to backup TO a RAID. I'm having issues backing up a RAID TO time machine. The internal disk backs up great, but the RAID only backs up the mount point (an empty folder), not what's inside it.

The folder isnt in the exclude list and both my account and admin have full disk access privelages.

Thanks

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Answer 5

avikb123 Author

Level 1

4 points

Aug 19, 2025 09:25 AM in response to avikb123

Solution to the situation, not a solution to the problem. I migrated the RAID data on to two external disks and disconnected the RAID.

The two separate external disks backup with time machine fine.

Still don't know why the RAID didn't backup.. but now at least I have DR capabilities.

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Answer 6

avikb123 Author

Level 1

4 points

Aug 17, 2025 09:08 AM in response to Rudegar

Someone on another tread suggested another backup app... but I like how time machine is integrated into macOS's recovery and cloning capabilities.

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Answer 7

Aug 19, 2025 09:48 AM in response to avikb123

<< Still don't know why the RAID didn't backup. >>

Conventional Wisdom:

MacOS needs NATIVE formatted disks as the drives it can back up FROM. The usual "big surprise" is that it can not back up Windows format drives, even with third-party Utilities that allow Reading/Writing of NTFS drives. Other "surprises" can be Network drives or Cloud drives.

We do know that RAID drives are not handled by the "regular" MacOS driver. This is to prevent single drives from being damaged by ordinary single-drive logic in MacOS. Instead, a special RAID driver is installed on each drive, and that may make the drives look different to Time Machine.

Either:

• you have discovered experimentally another format of drive that it can not backup FROM

-OR-

• you have uncovered a Bug, and perhaps it SHOULD be able to backup such drives

If you think it might be a Bug, contact Support and explain to the First Responder why you think this is a Bug. Be polite and professional, and ask for a Specialist to contact you to pursue a solution (or get on record with a formal, tracked BugReport).

Official Apple Support

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