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

Arno Wagner arno at wagner.name
Wed Dec 2 13:22:08 CET 2015


I second that. I have some experience with handling large 
data-sets. Doing a verify after copying larger amounts of data 
is one of the better ways to identiify problems with RAM, 
busses and controllers.

Regards,
Arno


On Wed, Dec 02, 2015 at 09:04:10 CET, Ritesh Raj Sarraf wrote:
> 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 ?
> 
> 
> Ritesh
> 
> 
> 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
> > > 
> > > 
> > > _______________________________________________
> > > dm-crypt mailing list
> > > dm-crypt at saout.de
> > > http://www.saout.de/mailman/listinfo/dm-crypt
> > _______________________________________________
> > dm-crypt mailing list
> > dm-crypt at saout.de
> > http://www.saout.de/mailman/listinfo/dm-crypt
> -- 
> Given the large number of mailing lists I follow, I request you to CC
> me in replies for quicker response
> 



> _______________________________________________
> dm-crypt mailing list
> dm-crypt at saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt


-- 
Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
A good decision is based on knowledge and not on numbers. -- Plato

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier


More information about the dm-crypt mailing list