Re: [gentoo-user] Re: Fast checksumming of whole partitions

[Manuel Klemenz <m.klemenz@gmx.at>]

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I'm calculating checksums over partitions just by calling
# md5sum /dev/sda1
or for the complete disk (incl. partition table + all partitions)
# md5sum /dev/sda

that's it :) - works with any distro/liveDVD

-- 
Cheers,
Manuel Klemenz

On Saturday 05 June 2010 21:23:31 meino.cramer@gmx.de wrote:
> 7v5w7go9ub0o <7v5w7go9ub0o@gmail.com> [10-06-05 20:22]:
> > On 06/05/10 02:39, meino.cramer@gmx.de wrote:
> > []
> > 
> > > Is there any faster and reliable way to checksum whole paritions (not
> > > on "per file" base)???
> > 
> > FWIW, portage has a tool called "dcfldd" that works well for me. It is
> > 
> > dd with the addition of:
> >       *   Hashing on-the-fly - dcfldd can hash the input data as it is
> > 
> > being transferred, helping to ensure data integrity.
> > 
> >       * Status output - dcfldd can update the user of its progress in
> > 
> > terms of the amount of data transferred and how much longer operation
> > will take.
> > 
> >       * Flexible disk wipes - dcfldd can be used to wipe disks quickly
> >       and
> > 
> > with a known pattern if desired.
> > 
> >       * Image/wipe Verify - dcfldd can verify that a target drive is a
> > 
> > bit-for-bit match of the specified input file or pattern.
> > 
> >       * Multiple outputs - dcfldd can output to multiple files or disks
> >       at
> > 
> > the same time.
> > 
> >       * Split output - dcfldd can split output to multiple files with
> >       more
> > 
> > configurability than the split command.
> > 
> >       * Piped output and logs - dcfldd can send all its log data and
> > 
> > output to commands as well as files natively.
> > 
> > 
> > e.g. when I copy my HD, I get a copy status report and hash by using the
> > following commands:
> > 
> > #!/bin/bash
> > dcfldd if=/dev/sda bs=4096k sizeprobe=if status=on hashwindow=0
> > of=/dev/sdb dcfldd if=/dev/sdb bs=4096k sizeprobe=if status=on
> > hashwindow=0 of=/dev/null
> > 
> > When they've completed, I'll visually compare the two hashes (you can
> > automate this.) You can get fancier and do the Verify instead of the
> > hashes.
> > 
> > HTH
> > 
> > (p.s.  Part of your answer is setting the best blocksize for dd or
> > dcfldd.
> > 
> > I'd presume it the smaller of your available memory, or the buffer size
> > on your HD?...... someone please correct me on this!?)
> 
> That looks really interesting. The only problem I have with this is
> that I have to have /dev/sda as /dev/sdb idle (not mounted) and
> because of that I use knoppix as temporary system to boot. And I
> dont think that knoppix has this tool "on board".
> 
> Or is there a way to do such copies from a one disk to another
> while one disk is booted???
> 
> Best regards,
> mcc

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