[Discuss] USB speeds

[gaf at blu.org (Jerry Feldman)]

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On 08/29/2011 03:05 PM, Rich Pieri wrote:
> Two factors come immediately to mind, neither of which have anything to
do with the bus.
>
> On Unix, file systems are mounted asynchronously by default. I've seen
this cause horrible performance degradation on USB flash media. Try
mounting sync instead.
>
> You neglected to specify a block size so dd defaults to 512 byte
blocks. This is horribly inefficient. Try powers of 2 starting at 1MB to
find an optimal value.
>
When I use dd to copy an image I make sure that the device is not
mounted. Note that I am copying to the device.
I think that when I copied the image, I did use bs=1MB. As I mentioned,
I will plan to run a benchmark test tomorrow in my office if all my
servers come up ok.

- -- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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