On Sunday 06 June 2010 11:19:57 Andrea Conti wrote: > > 1. boot up knoppix > > 2. create a partition: mkdir /work > > 3. mount /work to the root partition: mount /dev/sdc /work > > 4. cd /work/usr/bin > > 5. run dcfldd: ./dcfldd > > This is fine, provided that > > 1- if the root partition is [part of] what you're copying, you *must* > mount it read-only (mount -o ro /dev/sdc /work) > > 2- the dcfldd executable is linked statically. If it uses dynamic > linking, your "live" system -- knoppix in this case -- must have exactly > the same library versions (especially glibc) as the gentoo system. > > >> Or is there a way to do such copies from a one disk to another while > >> one disk is booted??? > > The point is not with being "booted" (i.e., part of the running system) > or not: you *cannot* reliably perform a sector-by-sector copy of any > write-mounted partition without special support either at the FS or > block device level (i.e. snapshots). > > > Sure, but the running disk/sector would have temporary files that would > > not consistently hash when you did the hash check. > > That is only a minor part of the problem. The real issue is that if > *anything* writes to the source partition while you are halfway through > copy, you risk ending up with inconsistencies in the filesystem > metadata. Doing a fsck on the copy will probably fix that, but you risk > losing or corrupting data. > > And no, hashing as described in the previous post will *not* catch any > differences in this case, as the "source" hash is computed from what is > read during the copy (which, barring hardware problems, is what gets > written on the target disk) and not from the whole contents of the > source partition after the copy (or at any single point in time). > > > If you do this, try it in linux without bringing up X. > > That's definitely not enough: at the very least, boot up in single-user > mode and remount all your partitions read-only (mount -o remount,ro). > This will break things on a running system (e.g anything that writes to > /var and /tmp will throw errors or stop working), but it will allow you > to produce consistent partition images.
It may be worth trying 'apt-get install dcfldd' after you su to root with Knoppix. As long as Knoppix does not need a lorry load of dependencies you may be able to quickly install the .deb binary you need and move on with the task in hand. -- Regards, Mick
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