I tried with cat > /dev/sdb at the end of the command and then with of=/dev/sdb

the error message every time was following:
pv: -s: integer argument expected

I'd get rid of the whole timing deal and go back to simple if of.

I use rsync. On the next line I will paste the shell script I use to do this. In my case I have then set up a cron job to automatically back up my complete home directory and all other users in it every night at 9 PM Then also on Mon night at 10 PM I then make a weekly backup. I will post both scripts and u will notice the different folders they go into. This operation takes approximately 7 minutes to do. Size of my home directory at the moment is around 84 Gbs. Note using rsync, the first copy takes awhile because it has to back up all files, subsequent backups then take the seven minutes or so, this is because the script is set up to mirror the differences from the hard drive. Also a daily log is made. On my distro (PCLinux OS o9) Rsync was one of the programs installed with base installation. Google Rsync and you will see what the options I have set up with this script are doing. The idea behind the weekly and daily bkups is that I then have 7 days to see if I have a problem with my system and roll back to a known good version if required..

Daily bkup
#!/bin/bash
#Script to back up my home directory minus movies and music dirs daily
rsync --archive --exclude=You\ Tube\ Videos/* --exclude=Movies/* --delete --log-file=/media/SAMSUNG/daily/jrp-log /home/jrp /media/SAMSUNG/daily/

Weekly backup
#!/bin/bash
#Script to back up my home directory minus movies and music dirs Weekly
rsync --archive --exclude=You\ Tube\ Videos/* --delete --log-file=/media/SAMSUNG/weekly/home-log /home /media/SAMSUNG/weekly/

Note: You will have to input your own directorys and backup destination. My destination is on a external 2Tb Samsung drive with a file called weekly and daily. To restore is simply a matter of reinstalling base distribution and then copy required files from the backup drive. Note if you have more experience than I do, you probably will save a bit of time backing up relevant files from root.
Hope this helps, Cheers .

If you are using Red Hat or Fedora they have a great gui utility called fwbackups that lets you setup your local machine backups quite easily. I'd not recommend it if you need to backup more than 2-3 machines (for that use something like bakula or amanda.)

Thanks for the info.

I tried with "dd" first, but I think I can forget about it. I made a disk to disk copy and it took more than 6 hours for 124 GB, 5,5 MB/s
That isn't what I was looking for.

Then there is huge problem or you have major large and slow disks.

Try G4U. It is basically dd but I think you can enable dma with some boot option if that is the issue.

Both disks are WD 160 GB and with 20% data on it.
I tried to make an image file to an external USB disk and it happend following: 2 hours 14 GB (I interrupted it)

It's weird that when I make an image file from the partition it takes only 10-15 minutes.
For me it's hard to understand why the system not shows the progress. (the percentage) if I use "dd if=/dev/sda of=/dev/sdb"

on the other hand it shows the progress if I use "dd if=/dev/sda of=/mnt/PC_name/backupMBR.1 count=1 bs=512"

is the "count=1" which help me to see the progress?

NO, "count" parameter is not for progress.

For E.g.
This will create a 20 MB file ..... ( 2 x 10 )