[dm-crypt] LUKS linux encrypted file system causing file corruption

Ritesh Raj Sarraf rrs at researchut.com
Wed Dec 2 09:04:10 CET 2015

Did you get a chance to verify what Ralf and Arno asked for ?

I'd too, be interested to know the findings. In the initial post, you
did not mention what file system you were on ?

Also, interesting is Ralf's point. Are you copying the file while it is
opened by another process ?


On Mon, 2015-11-30 at 13:47 +0100, Ralf Ramsauer wrote:
> Hi Sumit,
> a change of the checksum implies that the source and destination file
> differ. The reason why it differs is another question.
> Does the checksum also differ if you copy it from unencrypted to
> unencrypted?
> First, please check your dmesg log if something suspicious occurs
> during the copy process. A hard drive failure might also explain your
> problem. As you're using VMs, check the dmesg of the hypervisor
> machine which accesses the actual hardware.
> Second, ensure that the source file is not changed during the copy
> process and also not afterwards when comparing the checksums. Same
> applies to the destination. You might want to use 'lsof' to check if
> some process is accessing the file.
> Just a guess - ...you mentioned VMs and a file of around 5GB...
> Sounds like you're trying to copy a VM image, eh?
> If so, make sure that your virtualization software does not touch the
> file during copy.
> Cheers
>   Ralf
> On 11/30/2015 10:19 AM, Sumit Kumar wrote:
> > I am having a LUKS encrypted Linux file system (dmCrypt). When I
> > copy a huge file, around 5 GB of file, from un-encrypted linux file
> > system to LUKS encrypted linux file system then the target copied
> > file MD5 changed.
> > I am not sure does it corrupting the file as the MD5 changed?
> > I am using CentOS 6.5 and working on VMs not on physical machine. 
> > Any help will be greatly appreciated . 
> > 
> > -- 
> > Thanks & Regards
> > Sumit Kumar
> > 
> > 
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