Nikos Chantziaras <rea...@arcor.de> [10-06-05 10:08]: > On 06/05/2010 09:39 AM, meino.cra...@gmx.de wrote: > > > >Hi, > > > > this night dd copies the contents of my first > > 1TB disk to my second 1TB disk (same Model). > > > > (dd if=/devsda of=/dev/sdb bs=4096) > > > > I want to verify, that the copy is identical. > > > > I tried (or: I am still trying) to checksum > > the first disk with > > > > whirlpooldeep /dev/sda > > > > whch seems to work but is DAMN slow (in relation > > to checksumming 1TB in whole). > > > > Is there any faster and reliable way to checksum > > whole paritions (not on "per file" base)??? > > > > Thank you very much in advance for any help! > > > > Best regards, > > mcc > > Constructing a checksum means reading every byte off the partition. So > it's slower as a copy to /dev/null, never faster (because the checksum > calculation also needs time.) > > So in order to determine whether it's really slow, compare the time > needed to dd the whole partition to /dev/null to the time needed for > checksumming it. Then post the times here and an expert might then > tell whether this can be improved at all or not. >
Since the following is only some "info in between" I answer not one of the last posting, which only means, that this post somehow is related to this fred but not as a direct reply. I downloaded the current "Parted magic" which - copies itsself completly to RAM if wanted and runs from there which gives you back the dvd/cdrom drive for other things. - contains a lot of get-out-of-a-desaster-tools combined with tools to play low level games with harddiscs - contains dcfldd (!). With this and dcfldd I copied one 1TB WD10EARS disk on a SATA1 controller to another harddisk of the same model with this timings (sda ==> sdb): real: 293m17.265s user: 113m59.072s sys : 64m6.605s Checksumming the second disk while copying its contents to /dev/null reveals this timnings (sdb==>null: real: 253m57.517s user: 113m51.988s sys : 32m21.381s Again: The transfer was via SATA1 and the disks were jumpered to use SATA1 speeds only. Despite a lot of CRC-error reported via dmesg/kernel logs the copy was identical to the original. As mentioned, I think the via pata conflicts with via sata in earlier kernels, since I do not see these messages with 2.6.34.00. I will check for sdd on the Parted Magic iso and post later what I did find. Does anyone has experiences with gparted? Is it recommended (I need support for ext4)? Best regards, mcc -- Please don't send me any Word- or Powerpoint-Attachments unless it's absolutely neccessary. - Send simply Text. See http://www.gnu.org/philosophy/no-word-attachments.html In a world without fences and walls nobody needs gates and windows.
