USB Hard Drive Activity Slows down Host

[Les Mikesell]

On Mon, 2006-06-19 at 12:22 -0700, Hugh Caley wrote:
> We regularly copy a few hundreds of gigabytes of data from a host 
> running Fedora to a LaCie USB 2 hard drive in order to ship the data to 
> an overseas company.  We've noticed that initiating the copy causes the 
> load on the machine to creep up and the machine to become very slow in 
> response.  Stopping the copy causes the load to slowly come down again.
> 
> Machine is a quad processor (or dual dual-core) AMD Opeteron box running FC3
> 2.6.12-1.1381_FC3smp #1 SMP Fri Oct 21 04:22:48 EDT 2005 x86_64 x86_64 
> x86_64 GNU/Linux
> 
> dmesg info:
> 
>   Vendor: LaCie     Model: BigDisk           Rev:    
>   Type:   Direct-Access                      ANSI SCSI revision: 00
> SCSI device sdc: 976794336 512-byte hdwr sectors (500119 MB)
> sdc: assuming drive cache: write through
> SCSI device sdc: 976794336 512-byte hdwr sectors (500119 MB)
> sdc: assuming drive cache: write through
>  sdc: sdc1
> Attached scsi disk sdc at scsi6, channel 0, id 0, lun 0
> usb-storage: device scan complete
> 
> 
> There are no error messages.  Any ideas?

I think there is quite a bit of CPU overhead in transferring
data through a USB controller.  Firewire might be more
efficient if it happens to work in the kernel version you
are using (there have been problems over the last year or so).

-- 
  Les Mikesell
   lesmikesell at gmail.com