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Is there any way I can connect 14 different external USB hard disks together to a Windows 7 64 bit desktop PC? My system has only two USB ports. I want to mount all these external disks together as different drives in the system.

Right now, I am able to connect one External hard disk using the PC USB port.

I have read that there are USB Hubs available which provides 10 USB ports. Has anybody tried USB hubs to connect more external hard disks (more than 6)? Is there any known issues like performance difference from connecting them like this?

5 Answers5

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Your USB interface is going to be a bottleneck. You can daisy chain up to 128 devices with USB, though, you'll need to use powered drives of powered hubs.

If it's just a matter of space, it could work. You could probably use a pair of 8/9 port hubs, or chain up USB drives like so

                               +----+                         
                   USB Hub 1   |    +--------->Powered hub 1  
                    4x ports   |    |                         
                    unpowered  |    +---------> Powered hub 2 
<------------------------------+    |                         
    USB to PC                  |    +----------> Powered hub 3
                               |    |                         
                               |    +----------> Powered hub 4
                               +----+                         

Or split it in half with 2 powered hubs hanging off an unpowered one.

I'd take note of the USB drive's power usage (If it's a 2.5 inch drive) and the power supply capacity of the powered hubs. If the powered hubs aren't giving enough power for the drives you are using, you may need to split off some drives into another powered hub. If you're using drives with a separate power supply, you cannot worry about power supply from the hubs.

I've done some back of the envelope calculations based off hardware I have - I have a Toshiba Canavio HDD that's rated for 5V/1A and my Belkin USB hub has a 2.6A power supply. If I wanted to play it safe, I'd have at most 2 self-powered USB drives per powered hub, maybe 3-4 if I felt adventurous. I'd test to make sure this actually works with all 4 drives plugged in, and while loading all 4 drives simultaneously.

On Windows, I would probably consider the matter of running out of drive letters, but it's only 16 drives.

I'd add this is a pretty horrid set up. You're going to have speed constrained to the USB ports you use, you're going to have a spider's mess of cables, troubleshooting will be a pain, since you have multiple points of failure and so on.

Pang
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Journeyman Geek
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I bought a 7-port USB hub with (theoretically) 1A of external power. But it does not support more than 2 non-powered USB 2.5" drives... so if you have electronic skills, my sugestion is to:

  1. Connect the big hub (with or without external power) into the computer
  2. Hack the USB cable (the one that connects the HDD to the HUB) to receive power from an external font, like an hacked ATX-desktop font: Can I safely connect the power-only-end of a USB-Y cable to an other power source?
  3. Connect how many (<127) drives you want.

Just remember that performance will be quite bad when using more than one drive at once. If performance is an issue, look for PCI/USB cards to plug into your desktop computer.

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I've done it with XP. You can use multiple hubs if you want--hubs may be plugged into hubs up to the device limit. Note that hubs count as devices, hubs with many ports sometimes count as more than one device.

You will take a performance hit but so long as it's not a bunch of stuff you'll need all at once the hit will be minor.

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In my personal experience, it will always be slower to use external drives, rather than internal drives. But I have connected USB hubs to USB hubs before, so I don't see any reason why you shouldn't be able to connect 16 drives to 1 USB port, if only you have enough USB hubs... You might want to buy an I/O card with extra USB ports, that is if it's not a laptop.

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The way with USB HUBs works technically, no serious issues but performance. If you are not going to spend more money you can go for it. It's cheapest but slowest way.

However I would run it on professional stuff, such as SAS. Here is an example which would cover you requirements:

15 SAS or SATA drives in one box with SFF-8088 miniSAS connections for great storage density, SAS reliability and performance. Imposes no bandwidth restriction on drives. Trayless design allows easy installation and effortless hot-swapping. Reliable 460W Zippy server-grade power supply. Ideal desktop direct-attached mass-storage solution for non-RAID or software RAID applications enter image description here

it's cost is about $700 for now and can be found here

That's for external 14.

If you had less, say 4, and it is Desktop Case (not Laptop) it can be run through an additional PCI board inside your Desktop Case, but that's another story.