View the Most Wanted LQ Wiki articles.
Go Back > Forums > Linux Forums > Linux - Hardware
User Name
Linux - Hardware This forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?


  Search this Thread
Old 02-14-2013, 01:40 AM   #1
LQ Newbie
Registered: Jul 2005
Posts: 9

Rep: Reputation: 0
>33 USB drives, is it possible?

So I'm trying to install more than 127 usb devices into one computer for a project for school.

Every year my school hands out a bunch usb drives to each graduate. I managed to get permission to borrow them before they hand them out.

I want to raid them all together.
-- For science.

Why 127?
--It's the maximum theoretical limit, per host controller

Hubs count towards the 127 device limit.

The problem I'm having is I can't get an operating system to recognize more than 36 of them at once.

Here are my results so far.

Windows 7 turns off the usb port at 36 usb drives and I have to unplug all the usbs and restart to get it working again.

Linux (Ubuntu 10.04) stops recognizing more usb drives after 33. I have no clue why it is failing so far short of 127.

The box has 4 externally powered 10 port hubs, each with 10 usb drives plugged into them which is then plugged into the motherboard. From a power consumption standpoint this should be providing 1.5Amps to each hub and each drive shouldn't be pulling more than 100mA when constantly writing. So I should be good.

ChromeOS (linux I know) stops recognizing drives after 16, haven't played with dev mode.

OSX does funky stuff when 20 get plugged in, it somehow recongizes 23.

Has anyone else dived down this path before?

Proof I'm not just messing with you guys is attached.

Quick update. I got to 99 drives using 12 hubs. Seems to be a power issue. Windows reports each drive is using 200mA. If you start with 5 drives and add one at at time it will go past the 33 drive limit I was dealing with. Windows BSOD'd on me so I'm gonna try with linux and order more hubs so I can spread it out more.
Attached Thumbnails
Click image for larger version

Name:	427208_10151500309664402_1445402168_n.jpg
Views:	20
Size:	104.3 KB
ID:	11833   Click image for larger version

Name:	ubuntu.png
Views:	16
Size:	247.4 KB
ID:	11835  
Attached Files
File Type: txt usblog.txt (2.5 KB, 10 views)

Last edited by jimbob3000; 02-14-2013 at 03:12 AM.
Old 02-14-2013, 09:48 AM   #2
Registered: Jan 2005
Location: Midwest USA, Central Illinois
Distribution: SlackwareŽ
Posts: 11,934
Blog Entries: 15

Rep: Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664Reputation: 1664
Member Response


Look at: Programming Guide for Linux USB Device Drivers

How are you chaining the USB hubs to the system? Cable lengths between hubs? As to the power requirements, you should consider isolating each external hubs that you now have and providing more external power to each.

I am curious as to why and what you are going to use that many external USB devices.

As for Linux, you will need to look at the kernel USB driver and configuration.
Old 02-14-2013, 04:52 PM   #3
LQ Guru
Registered: Mar 2008
Posts: 13,492

Rep: Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718Reputation: 1718
I'd be ordering more pci-e to usb adapter cards.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Any problems with USB-port PCMCIA cards and USB Floppy Drives? DreameR-X Linux - Laptop and Netbook 9 05-14-2005 01:37 PM
usb drives jbzy3000 Fedora 2 02-16-2005 12:04 PM
udev, USB Flash Drives, and usb-mount talkingwires Debian 13 11-07-2004 12:15 PM
Give user permission to mount/use cdrom drives or usb drives zwyrbla Linux - Newbie 2 08-23-2004 04:30 PM
Where are my USB drives ? Forpus Linux - Hardware 5 06-26-2004 08:42 AM

All times are GMT -5. The time now is 07:49 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration