USB Hard Drive Activity Slows down Host

[Hugh Caley]

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?

Hugh

-- 
Hugh Caley | Unix Systems Administrator | CIS
AFFYMETRIX, INC. | 6550 Vallejo St. Ste 100 | Emeryville, CA 94608
Tel: 510-428-8537 | Hugh_Caley at affymetrix.com