# Connecting multiple SSD drives to same USB hub?



## erikradbo (Dec 9, 2020)

Hi,

I run an iMac 27" mid 2017 with max specs, having 2 USB-C's and 4 USB 3 ports. I have a lot of gear connected, so I'm using two powered USB hubs which occupy two of the ports ports, then two external SSD's, my sound card and a secondary screen in the other four ports. I just got one more SSD though, so now I have to rethink. A hub is just splitting the speed of that USB port between the hub ports IIRC, so connecting two SSD's to a hub would then be a bad idea, wouldn't it? Or does the speed of the USB ports succeed the SSD's to the extent is doesn't matter if they share the port?

Currently I have some issues with some midi controllers dropping out needing to reconnect, which would be nice to solve at the same time.

What's the optimal solution for connecting this:
- Logic Keyboard (needing 2 usb ports)
- Midi keyboard 1
- Midi keyboard 2
- Midi controller 1
- Midi controller 2
- Midi breathing controller
- External soundcard
- Ext SSD1
- Ext SSD2
- Ext SSD3
- Ext HDD
- Second screen / projector

- And an extra port for charging trackpad when needed

I'm assuming that sound card + 3 SSDs should go straight into the computer, then getting a larger powered usb hub for keyboard, midi controllers and the HDD. Any thoughts?

Edit: typo


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## jbuhler (Dec 10, 2020)

I’d pick up a Thunderbolt hub. If you have thunderbolt 3 they are readily available. Thunderbolt 2 hubs are hard to find, but fortunately most TB3 hubs are backwards compatible as long as you get the TB2 to TB3 adapter from Apple. This will increase your USB ports by 4 or 5 depending on the model and you can run your monitor through that. You can then connect your SSDs to that and they will have enough bandwidth that the streaming of samples shouldn’t suffer. Vice versa you could get something like a Thunderbay mini and put your SSDs in that and also run your monitor through that. I would also get a good large powered USB 3 hub and run all your midi gear into that. None of the midi gear I have is particularly fussy so long as the USB hub has enough power to run it all. I’m guessing your drop outs are more likely a power issue than a data rate issue. Interface can go into open USB port or open TB port depending on the type you have. The Logic USB keyboard might be able to go in a USB hub too.

I have a very similar set up and use both a TB3 hub and two Thunderbays (the two of them hold 8 SSDs total). The TB3 hub gives me 4 USB3 ports, a powered USB-C port, a TB3 port and a DisplayPort. The thunderbays are daisy chained together, and one of them also has a DisplayPort. My two external monitors go into those DisplayPorts. I also have two powered USB3 hubs; they give me 15 additional powered USB 3 ports.

cable management and labeling is also important in this kind of set up, as is getting enough outlets located with good proximity. I’ve taken to mounting powerstrips on the underside of the desk and investing in cable ties and snakes, also mounted to the underside of the desk.


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## erikradbo (Dec 11, 2020)

jbuhler said:


> I’d pick up a Thunderbolt hub. If you have thunderbolt 3 they are readily available. Thunderbolt 2 hubs are hard to find, but fortunately most TB3 hubs are backwards compatible as long as you get the TB2 to TB3 adapter from Apple. This will increase your USB ports by 4 or 5 depending on the model and you can run your monitor through that. You can then connect your SSDs to that and they will have enough bandwidth that the streaming of samples shouldn’t suffer. Vice versa you could get something like a Thunderbay mini and put your SSDs in that and also run your monitor through that. I would also get a good large powered USB 3 hub and run all your midi gear into that. None of the midi gear I have is particularly fussy so long as the USB hub has enough power to run it all. I’m guessing your drop outs are more likely a power issue than a data rate issue. Interface can go into open USB port or open TB port depending on the type you have. The Logic USB keyboard might be able to go in a USB hub too.
> 
> I have a very similar set up and use both a TB3 hub and two Thunderbays (the two of them hold 8 SSDs total). The TB3 hub gives me 4 USB3 ports, a powered USB-C port, a TB3 port and a DisplayPort. The thunderbays are daisy chained together, and one of them also has a DisplayPort. My two external monitors go into those DisplayPorts. I also have two powered USB3 hubs; they give me 15 additional powered USB 3 ports.
> 
> cable management and labeling is also important in this kind of set up, as is getting enough outlets located with good proximity. I’ve taken to mounting powerstrips on the underside of the desk and investing in cable ties and snakes, also mounted to the underside of the desk.



Thanks, I have two usb-c ports which I believe is the same as tb3. Do I understand it correctly that the speeds are higher on these than on normal USB ports so that sharing a tb3 port between ssds with a hub won’t be an issue for the speed of the ssd’s.


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## jbuhler (Dec 11, 2020)

erikradbo said:


> Thanks, I have two usb-c ports which I believe is the same as tb3. Do I understand it correctly that the speeds are higher on these than on normal USB ports so that sharing a tb3 port between ssds with a hub won’t be an issue for the speed of the ssd’s.



The USB-C ports on the Macs are also TB3. But once it leaves the Mac other devices might be one or the other, so you need to be careful, especially in the order you connect devices. TB3 has much faster speeds. I believe USB-C is faster than standard USB3 but I can't say for sure since I don't have any USB-C drives. I do know that 4 SSDs on a single TB3 chain will run fine on TB3—I'm about to test adding another 4 SSDs to that chain. I've also found in practice that two SATA SSDs mounted in a 2 disk bay work ok on a standard USB3 port, but not more.


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## rnb_2 (Dec 11, 2020)

Just adding a bit of technical detail: Thunderbolt 3 has 8x the bandwidth of a typical USB3 port (40Gb/s vs 5Gb/s), so even 4 USB3 SSDs will only use ½ of the total available bandwidth. However, most Thunderbolt devices that support video (via HDMI, DisplayPort, or Thunderbolt chaining) reserve some bandwidth for a video data stream, typically about 8Gb/s, reducing total bandwidth for everything else to 32Gb/s.

USB-C devices can be either USB 3.2 Gen1 (5Gb/s) or Gen2 (10Gb/s), so can theoretically use twice as much bandwidth as a USB3 port if the latter (there is also a rarely-supported Gen2x2 at 20Gb/s). Also, Thunderbolt 3 can daisy-chain devices, so you'll sometimes find TB3 drives with two ports on them to support this (these are typically multi-drive RAID enclosures, like @jbuhler's Thunderbays). USB 3.2 can't be daisy-chained, so if you plug a USB-C device into a Thunderbolt port, it will be the end of the Thunderbolt chain, by definition.


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## erikradbo (Dec 12, 2020)

rnb_2 said:


> Just adding a bit of technical detail: Thunderbolt 3 has 8x the bandwidth of a typical USB3 port (40Gb/s vs 5Gb/s), so even 4 USB3 SSDs will only use ½ of the total available bandwidth. However, most Thunderbolt devices that support video (via HDMI, DisplayPort, or Thunderbolt chaining) reserve some bandwidth for a video data stream, typically about 8Gb/s, reducing total bandwidth for everything else to 32Gb/s.
> 
> USB-C devices can be either USB 3.2 Gen1 (5Gb/s) or Gen2 (10Gb/s), so can theoretically use twice as much bandwidth as a USB3 port if the latter (there is also a rarely-supported Gen2x2 at 20Gb/s). Also, Thunderbolt 3 can daisy-chain devices, so you'll sometimes find TB3 drives with two ports on them to support this (these are typically multi-drive RAID enclosures, like @jbuhler's Thunderbays). USB 3.2 can't be daisy-chained, so if you plug a USB-C device into a Thunderbolt port, it will be the end of the Thunderbolt chain, by definition.



Ok. So even if the connection looks the same I have to be careful if actually connects with TB3 or USB-C, since the former has 4x the speed?


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## erikradbo (Dec 12, 2020)

jbuhler said:


> I’d pick up a Thunderbolt hub. If you have thunderbolt 3 they are readily available. Thunderbolt 2 hubs are hard to find, but fortunately most TB3 hubs are backwards compatible as long as you get the TB2 to TB3 adapter from Apple. This will increase your USB ports by 4 or 5 depending on the model and you can run your monitor through that. You can then connect your SSDs to that and they will have enough bandwidth that the streaming of samples shouldn’t suffer. Vice versa you could get something like a Thunderbay mini and put your SSDs in that and also run your monitor through that. I would also get a good large powered USB 3 hub and run all your midi gear into that. None of the midi gear I have is particularly fussy so long as the USB hub has enough power to run it all. I’m guessing your drop outs are more likely a power issue than a data rate issue. Interface can go into open USB port or open TB port depending on the type you have. The Logic USB keyboard might be able to go in a USB hub too.
> 
> I have a very similar set up and use both a TB3 hub and two Thunderbays (the two of them hold 8 SSDs total). The TB3 hub gives me 4 USB3 ports, a powered USB-C port, a TB3 port and a DisplayPort. The thunderbays are daisy chained together, and one of them also has a DisplayPort. My two external monitors go into those DisplayPorts. I also have two powered USB3 hubs; they give me 15 additional powered USB 3 ports.
> 
> cable management and labeling is also important in this kind of set up, as is getting enough outlets located with good proximity. I’ve taken to mounting powerstrips on the underside of the desk and investing in cable ties and snakes, also mounted to the underside of the desk.



Which tb3-hub do you use? They are quite pricey, so want to make sure I get a good one, if I can’t get away with a usb c-hub...


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## rnb_2 (Dec 12, 2020)

erikradbo said:


> Ok. So even if the connection looks the same I have to be careful if actually connects with TB3 or USB-C, since the former has 4x the speed?



Yes, exactly.

I have this TB3 dock from OWC and have been very satisfied with it.


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## jbuhler (Dec 12, 2020)

erikradbo said:


> Which tb3-hub do you use? They are quite pricey, so want to make sure I get a good one, if I can’t get away with a usb c-hub...


I have this one:



It’s worked well but I chose it because it was explicitly compatible with TB2, and my old machine only had TB2. It works well with TB3 as well. If you are just planning to add drives and run a monitor through this, it might be more space and cost effective to get a Thunderbay. The mini:



And the full sized one:



The difference is size of the unit, the bigger one has the power supply inside the unit and has a DisplayPort out, as well as TB3 through, the small one only has TB3 through.

if you go the Thunderbay route, be aware that the units have audible fans. I don’t find the sound irritating but if you are doing recording or are working at low volumes it might be a consideration.


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## erikradbo (Dec 12, 2020)

rnb_2 said:


> Yes, exactly.
> 
> I have this TB3 dock from OWC and have been very satisfied with it.





jbuhler said:


> I have this one:
> 
> 
> 
> ...




Geez, it's actually $249 "just" to split a connection. Thunderbay even more expensive. They better be good.


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## jbuhler (Dec 12, 2020)

erikradbo said:


> Geez, it's actually $249 "just" to split a connection. Thunderbay even more expensive. They better be good.


They don't "just" split connections. They set up a whole array of full USB3 ports (not just a hub), ethernet, card readers, full-powered USB-C, video out, as well as a TB3 through. These kinds of docks are the only real way to increase the bandwidth of USB3 on your mac, since USB3 hubs only increase the number of places to plugin, not the bandwidth that the USB3 port on the Mac can handle. A USB-C hub might have better performance than a USB3 hub because it can handle more data, but USB-C hubs do not seem to be that much cheaper.

Thunderbay is the equivalent of 4 Thunderbolt 3 enclosures and a TB3 through. It's expensive or not depending on what you want it to do and how much you value having it all in one unit rather than 4 units with all the resulting cables.


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## erikradbo (Dec 12, 2020)

jbuhler said:


> They don't "just" split connections. They set up a whole array of full USB3 ports (not just a hub), ethernet, card readers, full-powered USB-C, video out, as well as a TB3 through. These kinds of docks are the only real way to increase the bandwidth of USB3 on your mac, since USB3 hubs only increase the number of places to plugin, not the bandwidth that the USB3 port on the Mac can handle. A USB-C hub might have better performance than a USB3 hub because it can handle more data, but USB-C hubs do not seem to be that much cheaper.
> 
> Thunderbay is the equivalent of 4 Thunderbolt 3 enclosures and a TB3 through. It's expensive or not depending on what you want it to do and how much you value having it all in one unit rather than 4 units with all the resulting cables.



I get that, but that's the feeling, it's an unexpected cost for something I didn't consider a problem of that magnitude. Thanks for the guiding.


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## storyteller (Dec 12, 2020)

Whatever you do, you need to make sure you are addressing power and not just the number of ports. USB3 can draw up to 900ma per port with standard power draw (no fast charging)... so this means any usb hub needs a power supply that provides up to [email protected]~1amp per port to ensure all devices are able to draw their maximum amount required. This means you need about 4.5 watts per port on a usb hub. Do a little math to make sure the provided power supply has enough juice. Most USB hubs do not provide an adequate power supply. For example, a 7 port hub (fairly common) should be able to provide at least 32watts, and probably should include a 60watt adapter instead to ensure the fast charging ports work as they should.


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