[CentOS] slow usb hard disk performance.

Robert <kerplop at sbcglobal.net> wrote:
>     for dir in bin boot etc home initrd lib lost+found misc
> opt root \
>                sbin selinux srv tftpboot \
>                usr var ; do
>       find /$dir -depth -print0 | cpio --null -pmd $UD/$DT
>       echo `date` Completed: /$dir >>$PF
>     done

That's not a good benchmark.  You're adding the overhead of
inode/tree traversal and all sorts of other factors.  You're
easily cutting performance by 2-3x over.

Since USB 2.0 EHCI is capable of only 60MBps (480Mbps)
theoretical, and Intel openly admits that only 30MBps is
realistic, 8.8MBps is not unreasonable for this command.

Try a "raw" dd from /dev/zero, that is at least 2x your
memory:  
  dd if=/dev/zero of=(some file) bs=8M count=1000

Or consider a bonnie benchmark.


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