clievers
Site Admin
Joined: 07 Sep 2005
Posts: 164
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 Posted: Sun Oct 11, 2009 2:13 pm Post subject: Slow usb (?) |
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Was getting slow file copy. Found this page the suggested doing modprobe stuff. Putting here for future reference.
| Quote: | I don’t know when this happened but my external USB drives were running really slow. Reading RAW images off them took ages, backups took forever, and moving files back and forth was plain slow.
I use two Seagate FreeAgent external drives. They’re both USB 2 devices so should sustain more than the maximum 1MB/s I was seeing. I decided to go looking. First stop was /var/log/syslog where I found the following:
usb 2-1.2.4.4: new full speed USB device using uhci_hcd and address 13
usb 2-1.2.4.4: not running at top speed; connect to a high speed hub
To cut a long story short, after a few searches I found bug 66115 where the same problem is described. Unfortunately the ticket has since been closed but the work around discovered by Jean Pierre Rupp works for me too. I haven’t modified any files in /etc/ but unloading ehci_hcd and uhci_hcd and reloading in the correct order worked for me:
rmmod ehci_hcd
rmmod uhci_hcd
modprobe ehci_hcd
modprobe uhci_hcd
Now I get a very respectable 15-20MB/s when using rsync to transfer files from my internal drive and reads are super fast:
hdparm -tT /dev/sdi1
/dev/sdi1:
Timing cached reads: 3964 MB in 2.00 seconds = 1985.16 MB/sec
Timing buffered disk reads: 82 MB in 3.03 seconds = 27.08 MB/sec
Next on the TODO list is making sure the modules are loaded in the correct order on reboot. Time to dive into /etc |
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http://www.cory.lievers.ca |
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