Topic
4 replies Latest Post - ‏2013-12-05T23:36:48Z by ishimoto
omorin
omorin
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Pinned topic File size bigger on tape after copy with ltfscp

‏2013-04-26T12:39:28Z |

Bonjour,

When i use the ltfscp command in W2800R2, and i use the -sparse argument, the file copied on my ltfs tape are bigger than the original.

Any idea ?

  • HaraldSeipp
    HaraldSeipp
    7 Posts
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    Re: File size bigger on tape after copy with ltfscp

    ‏2013-05-02T08:59:16Z  in response to omorin

    Bonjour,

    the -sparse option is supposed to be used in case you have sparse files on disk that you want to copy efficiently to LTFS. As an example, VMs often use sparse files for efficiency and performance reasons. As LTFS supports sparse files, the ltfscp program is equipped with a mechanism to detect sparseness (areas within the file that contain zeroes) so that it can create a sparse file on LTFS during the copy operation.

    Assuming that the source files you used are indeed sparse files, it is hard to understand why different file sizes are reported on without additional information:

    • How did you determine the file sizes for LTFS and the source file and to what extent do the file sizes vary - exact values?
      Note that different file systems may show different allocation sizes although the data size is still the same.
    • Can you do a checksum on source and destination files or compare them - if these are identical, the source file was sparse, but for some reason, sparseness was not detected by ltfscp. In that case, the nature of the source file (application, content) would be important for further research

     

  • ishimoto
    ishimoto
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    Re: File size bigger on tape after copy with ltfscp

    ‏2013-09-19T15:09:11Z  in response to omorin

    Newer version of ltfscp fixed your problem with sparse option on Windows platform, and it is now available from IBM Fix Central web site at http://www.ibm.com/support/fixcentral/

    • digitalfilmstuff
      digitalfilmstuff
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      Re: File size bigger on tape after copy with ltfscp

      ‏2013-11-30T12:21:20Z  in response to ishimoto

      Hi there,

      On a similar note, I'm keen to get ltfscp working as restoring DPX image sequences off LTFS tape is proving incredibly slow.

      Apologies for a stupid question. I have a Quantum badged LTO5 drive, does this mean the IBM tools will not work?

      Mac OS X, currently using HP GUI interface. 

      Thanks in advance. 

      • ishimoto
        ishimoto
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        Re: File size bigger on tape after copy with ltfscp

        ‏2013-12-05T23:36:48Z  in response to digitalfilmstuff

        IBM tools (ltfscp) only works on the system running IBM LTFS software.