How many external SSDs can my iMac M1 manage?

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How many external SSDs can my iMac M1 manage?

I have an iMac M1. How many external SSDs (as backups) can my machine manage? Reason I ask is that I have three backup SSDs made by SanDisk. Operating well. But attaching a fourth SanDisk does not seem to work on a continuing basis. Sometimes I have to restart the iMac, and when I do that fourth SSD does not always load. Is that SSD corrupt or is it an indication that my machine can't handle the load?

I have an M1 iMac running macOS Ventura 13.2.1.

[Re-Titled by Moderator]

iMac 24″, macOS 13.2

Posted on Apr 7, 2023 9:07 AM

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Answer 1

Top-ranking reply

tbirdvet

Level 6

14,309 points

Apr 7, 2023 4:18 PM in response to danielfrombolingbrook

My previous Mac was a Mac Mini and I used a TB hub. Even with that when I tried to connect 4 drives at once it wouldn't see the last drive. I found that different drive enclosures acted differently as some probably took more current then the system could handle. All you can do is try to match or sort the drives the best you can that will provide the most reliable function.

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Answer 2

tbirdvet

Level 6

14,309 points

Apr 7, 2023 1:12 PM in response to danielfrombolingbrook

Depending on how these drives are connected you may be over loading the bus. I have a Mac Studio and if I try to connect too many TB drives in their own enclosure I get an error. These are all bus powered so if they had their own power they be supported but I have not tested that system yet.

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Answer 3

Apr 7, 2023 1:44 PM in response to tbirdvet

Your answer sounds likely, something I had not considered. I have three of the SSDs connected through an OWC Thunderbolt hub, but because there's only three USB-C inputs on that hub, I've connected the fourth (problematic one) to a USB hub, connected with a USB-C to USB cord. Maybe it's that connectivity that's an issue as well.

I'll have to eject that fourth SSD, not critical. At least I know the limit. If you know of a better way to connect it without buying another Thunderbolt hub (all the SanDisk SSDs are USB-C), please let me know. And thanks.

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Answer 4

Apr 7, 2023 7:17 PM in response to tbirdvet

Thanks for the input. Your experience with a fourth drive matches mine closely. I’ll remember all this going forward, and I’ve ejected the fourth SSD for now.

Right now I have a 1TB, a 2TB, and 2 4TBs connected, with only the 2 and 4s connected through the TB hub. Not sure, but the 1TB may not be a drag on the bus as it’s connected through a USB hub. I’ll keep an eye on everything for a few days, then try to swap out the 1TB with the now disconnected 4TB to see if that makes any difference.

Appreciate your help.

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Answer 5

Barney-15E

Level 10

116,182 points

Apr 8, 2023 5:16 AM in response to danielfrombolingbrook

Another aspect of USB is the throughput is shared. Not the same problem, but will become a problem if all drives are trying to read/write at same time.

You can daisy-chain thunderbolt drives and all will have same max theoretical speed.

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Answer 6

Barney-15E

Level 10

116,182 points

Apr 8, 2023 9:14 AM in response to danielfrombolingbrook

It has nothing to do with daisy-chaining. The USB spec is such that everything on the same bus shares the total potential speed. USB was designed for low-speed, low-data connections. The speed part has been improved, but the sharing of the bandwidth is still a flaw.

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Answer 7

Apr 7, 2023 12:27 PM in response to danielfrombolingbrook

Ventura 13.3.1 released today. Try this new updated version of Ventura.

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Answer 8

Apr 8, 2023 7:46 AM in response to Barney-15E

Understand daisy-chaining, but in this case my SSDs have just one input. So that configuration, although helpful with larger devices, is not possible here. Thanks anyway.

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Answer 9

Apr 8, 2023 3:39 PM in response to Barney-15E

Sorry. Didn’t realize your reply was about USB.

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How many external SSDs can my iMac M1 manage?

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