Tape Storage

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  • 1.  LTO 8

    Posted Thu December 03, 2020 04:48 PM

    Hi folks, I'm a brand new LTO-8 user and I have a question regarding LTFS (IBM Spectra) and available file space. After writing about 4tb to my first tape, my Windows Explorer is reporting that there's approximately 7tb of usable space (reported the full 10tb prior to writing) with 4tb free. Some research into the subject has made me aware that there are instances where LTFS does not report accurate information regarding the actual space available. Is there a free resource I can use to find out whether this enormous difference in space is due to bad sectors, over indexing, etc... ? Any help would be greatly appreciated as I cannot afford to experiment with 10tb tapes. Thanks in advance!


    Daniel Ryan

  • 2.  RE: LTO 8

    Posted Mon December 07, 2020 10:58 AM
    Edited by TAKESHI ISHIMOTO Mon December 07, 2020 07:07 PM
    I'm not aware of the case where IBM LTFS displays a wrong capacity number.   Could you point where you get that information?

    A couple of things you have to remember (regardless you use LTFS on Windows, or Linux or Mac).
    a) The usable space (remaining space or free space) indicates the amount of files you can write when none of files are compressible.   The tape drive has the built-in data compression function, and your file will be compressed on the fly.   Thus  the usable space decreases less than the bytes written.
    b) The space occupied by the deleted files on tape won't be freed up and the usable space won't increase until you completely reformat/wipe the tape.
    c) Due to the reasons above, the sum of active file size on tape + free space does not always equal to the native tape capacity (12TB for L8 media).

    I assume you are using the latest version of IBM Spectrum Archive Single Drive Edition.


  • 3.  RE: LTO 8

    Posted Mon December 07, 2020 10:59 AM
    Edited by TAKESHI ISHIMOTO Mon December 07, 2020 05:37 PM
    **removed the duplicated post**