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> USB is too slow, USB is really, really slow
Todd
 Posted: Dec 6 2011, 06:12 PM
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Hi All,

SL 6.1 x64

I have noticed that writes to my USB Flash Drives are a good 20 times slower than on my other CentOS 5.7 x32 machine AND on the same machine running Fedora Core 16 Xfce Live CDs. What use to take five minutes, now takes over two hours. (I now copy my large files to USB flash drive by booting off the live CD -- a real pain in the neck.)

Does running kvm have anything to do with this?

Anyone else notice this? And, did you come up with a work around?

Many thanks,
-T

$ cat /etc/redhat-release
Scientific Linux release 6.1 (Carbon)

$ uname -r
2.6.32-131.21.1.el6.x86_64

$ rpm -qa \*kvm\*
qemu-kvm-0.12.1.2-2.160.el6_1.2.x86_64

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helikaon
 Posted: Dec 11 2011, 10:19 PM
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Hi,
did you try to perform some kind of measures - e.g. like:
CODE

dd if=/dev/usb-device-FS of=/dev/null bs=1M count=10

to read from it
and
also write some 10mb file onto it (to compare reads/writes)
try it on different systems, post results, if you will ..

also, all your OSes is guest systems ...? What OS is host?

How is your devices recognised on different OSes?
post
CODE

lsusb -v

from all OSes ..

cheers,

This post has been edited by helikaon: Dec 11 2011, 10:22 PM


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Todd
 Posted: Dec 11 2011, 11:00 PM
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QUOTE (helikaon @ Dec 11 2011, 02:19 PM)
Hi,
did you try to perform some kind of measures - e.g. like:
CODE

dd if=/dev/usb-device-FS of=/dev/null bs=1M count=10

to read from it
and
also write some 10mb file onto it (to compare reads/writes)
try it on different systems, post results, if you will ..

also, all your OSes is guest systems ...? What OS is host?

Scientific Linux 6.1 x64
All the guests are off

It will take me a week or so to test

Thank you for the help!

QUOTE


How is your devices recognised on different OSes?
post
CODE

lsusb -v

from all OSes ..

cheers,

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Todd
 Posted: Dec 13 2011, 04:13 PM
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Seems I finally got around to doing my "yum upgrade". Got a new kernel. Now USB is back to full speed. Go figure ....

Thanks to everyone for their help and tips,
-T
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