USB ports running very slow
 

Coming to you guys to see if I get an answer to this problem. I'm still waiting for an answer from the Ubuntu forums. This is my problem:

I run Ubuntu 10.04 from an external drive (USB connected). A few days ago after doing some maintenance on my pc (increasing memory), apparently, I connected my hard drive to a different USB port. Now my boot process is extremely slow. When I go to the disks utility, it says that the connection is running at 12 MB/sec instead of 480 MB/sec. All disk activity now takes longer. Is this a bug on the OS? Changing to a different USB port shouldn't change the performance of disk activity. If it is, are there workarounds? Including information about my machine:

williepabon@WP-WrkStation:~$ uname -a
Linux WP-WrkStation 2.6.32-38-generic #83-Ubuntu SMP Wed Jan 4 11:13:04 UTC 2012 i686 GNU/Linux

williepabon@WP-WrkStation:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 10.04.4 LTS
Release: 10.04
Codename: lucid


williepabon@WP-WrkStation:~$ sudo hdparm -tT /dev/sdc
[sudo] password for williepabon:

/dev/sdc:
Timing cached reads: 84 MB in 2.00 seconds = 41.96 MB/sec
Timing buffered disk reads: 4 MB in 3.81 seconds = 1.05 MB/sec

Booting at above speed from a hard drive is essentially useless.

When I boot from a flash drive that has Ubuntu 10.10, these are the results of hdparm:

For the external hard drive(the one that has 10.04):

williepabon@Precision-WorkStation-670:~$ sudo hdparm -tT /dev/sdd
[sudo] password for williepabon:

/dev/sdd:
Timing cached reads: 1758 MB in 2.00 seconds = 879.50 MB/sec
Timing buffered disk reads: 94 MB in 3.03 seconds = 31.00 MB/sec

For the flash drive that I booted from:

williepabon@Precision-WorkStation-670:~$ sudo hdparm -tT /dev/sdc

/dev/sdc:
Timing cached reads: 1726 MB in 2.00 seconds = 862.85 MB/sec
Timing buffered disk reads: 84 MB in 3.05 seconds = 27.58 MB/sec

On both cases the disk utility says that the connection is USB at 480 MB/s. I know that this is the theoretical maximum. But, the results above may seem to indicate that Ubuntu 10.10 is managing the USB ports at the correct speed but Ubuntu 10.04 for some reason failed. I'm not interested at this time to upgrade to 10.10 (as somebody suggested) because 10.04 is the LTS version and all my critical files and data are done on that version. So, I want to fix the problem. Please, advise what other steps or tests I should make. Thanks again.

Hi there,

looks like some of your USB ports support USB 1.1 only. What does the mainboard's manual tell about that?

With the HDD connected to the same USB port as before?

[X] Doc CPU

Yes. No change on the USB port. The only thing I did was to plug my Ubuntu 10.10 stick to an available port and booted from it.

I'm sorry, but I'm not entirely sure what you're asking about. Aside from /dev/sdc, your numbers look completely correct. USB2 works at 480 mega*bits* per second, meaning aproximately a theoretical maximum of 48 megabytes per second, however the average speed I've attained over USB2 is typically around 9-30MBps, just like what you're getting. The only issue is how /dev/sdc is getting only 1MBps, which is what you'd expect from a USB1.1 port. Which port did you move it from and which did you move it to? Sometimes USB ports on the front panel will only run at USB1.1, and only the back ones will run at 2.0.

As I said in my original post, I get very low speed from the USB ports when I boot up With Ubuntu 10.04 that is on an external hard drive (usb). When I boot up with Ubuntu 10.10 that is on a flash drive (usb), I get the expected speeds to both the external drive and flash drive, as shown.

Just because it is the kind of thing I do not think of until I have tried a number of silly things, have you unpluged and repluged, several times, both ends of your usb cable to the external?

I have had this problem twice in the last 8 months with my external drive. This has fixed it both times. Of coarse the first time it took me about 4 days to think of it.

Cable connections, all kinds, need cleaned this way once in a while.

So do pci cards every once in a while.