[ltp] Re: Cloning a hard disk?

[Vijay Garla]

Hi,

using external usb 2.0 drives, i've seen wildly varying data transfer 
rates under linux (i've tried knoppix and suse). 
- Under windows, data moves quite fast
- Under linux, I see 1.6MB/s write speeds, and 23.6 MB/s reading speeds 
(this is much lower than the throughput should be on a USB 2.0 drive).

writing speed = 1.6 MB/s

dd if=/dev/zero of=/media/BACKUP1/test.out bs=1024 count=10240
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 6.56667 seconds, 1.6 MB/s

reading speed = 23.6 MB/s

dd if=/media/BACKUP1/test.out of=/dev/null
20480+0 records in
20480+0 records out
10485760 bytes (10 MB) copied, 0.444978 seconds, 23.6 MB/s


How do I speed things up?  This is a cheap, no-name usb enclosure, with 
a high-speed drive in it. 

TIA

- vijay

honey@gneek.com wrote:

> On Fri, 19 Aug 2005, Jaime Iniesta wrote:
>
>> It looks like my test didn't work. After 11 hours I aborted the process:
>>
>> root@0[dev]# dd if=/dev/hda of=/dev/uba bs=10M
>> 1895+0 records in
>> 1895+0 records out
>> 19870515200 bytes transferred in 40062.003484 seconds (495994 bytes/sec)
>>
>> Jaime
>
>
> Jaime - that looks like not even 0.5MB/s, so you've got a USB1 device
> there, or your system's not recognising a USB2 device correctly.  At
> that rate an 60GB disk might take... two days?  As per my previous
> mail, if you really have USB1, it's really not a good route - get a
> drive caddy?
>
> Honey