Spotlight abusing my NAS by indexing Time Machine backups all day long

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Level 1

22 points

Spotlight abusing my NAS by indexing Time Machine backups all day long

I have recently noticed that my Synology NAS is busy scanning hard drives all day long.

After a few hours of investigation I was able to narrow it down to Spotlight indexing my Time Machine backups.

It not only keeps the NAS hard drives working, causing huge power consumption and shortening their life time, it also keeps constantly downloading huge amounts (hundreds of gigabytes) of data from the NAS.

Forcing the Time Machine backup volume (mounted as hidden) to unmount stops the network traffic and indexing work immediately, but only until next scheduled Time Machine backup is done.

I was previously using AFP, tried to switch to SMB but that did not help.

Why is this happening and what can I do to fix it other than disabling Time Machine backups completely?

I'll deny any answer telling me this is normal or that this is necessary for Time Machine to work properly.

This is absolutely unacceptable. There is absolutely no reason to re-download all my backups over network only to index them and keeping my NAS and network busy all day long is not how backups are supposed to work. This is not protecting my data, it is in fact putting my data in risk of loss.

I am currently running macOS Monterey 12.6.8 on an M1 MacBook Pro.

MacBook Pro (2021)

Posted on Sep 12, 2023 1:28 AM

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Answer 1

hon-za-com Author

Level 1

22 points

Sep 13, 2023 8:31 AM in response to etresoft

I left it set to SMB. As a nasty temporary workaround, I installed TimeMachineEditor and scheduled the backups to run only once per day between 20:00 and 7:00, and I manually force-unmount the Time Machine volume every day when the backup is finished. This way the Synology stays silent most of the day.

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Answer 2

Jan 26, 2024 6:42 PM in response to hon-za-com

Well, I'm witnessing the exact same behavior.

Time Machine continuously hammers the NAS via SMB, all day long, with what I can only assume is some sort of indexing... even if the backup frequency is set to Daily or less frequently — it's just terrible. Enabling Spotlight privacy for the NAS shares doesn't work either. Anyhow, as of Sonoma (14.3), this problem has unfortunately still not fixed.

I fear the only solution is to abandon Apple's convenient, but inelegant, Time Machine backups for a better implemented 3rd-party backup software. Bummer.

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Answer 3

ku4hx

Level 7

23,694 points

Sep 12, 2023 1:34 AM in response to hon-za-com

If you care to tell Apple about Spotlight's unacceptable behavior: Product Feedback - Apple

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Answer 4

etresoft

Level 9

56,698 points

Sep 12, 2023 4:40 AM in response to hon-za-com

hon-za-com wrote:

I was previously using AFP, tried to switch to SMB but that did not help.

So what are you using now?

I have a Time Machine backup running on a Linux server over SMB and it works fine.

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Answer 5

Barney-15E

Level 10

122,318 points

Sep 13, 2023 3:26 PM in response to hon-za-com

Don't tell me that my Mac downloading hundreds of gigabytes from the NAS unnecessarily is the NAS fault. How would you explain that?

It shouldn't be downloading anything. The index is created on the drive itself.

I've got four Time Machine backups on external drives on my Mac (one local and three network) and Spotlight doesn't do anything noticeable with them. I agree, it sounds like a NAS problem.

APFS backups copy a snapshot to the backup drive, then that snapshot is reconciled with the snapshots on the drive. Maybe that's what you see happening. I don't think the reconciliation moves anything, though.

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Answer 6

VikingOSX

Level 10

123,470 points

Jan 27, 2024 7:55 AM in response to hon-za-com

Time Machine and Spotlight are interdependent. Expect a mounted NAS volume to be visited frequently when used as a Time Machine backup storage source. Where Spotlight stores is results has already been explained.

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