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Error while rebuilding RAID - 665 - file system limitation

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  • Error while rebuilding RAID - 665 - file system limitation

    While rebuilding a RAID configuration using OSForensics it is possible to encounter an error while writing the destination file. These files are typically enormous (100s of GB or even TBs)

    The error is,
    Error while rebuilding RAID.
    665 - ERROR_FILE_SYSTEM_LIMITATION - The requested operation could not be completed due to a file system limitation

    We believe this is due to file system fragmentation on the destination drive. Windows can only deal with about 1.5 million fragments per file. So exceeding this limit will result in an error.

    Possible solutions are,
    1. Pick a clean newly formatted destination drive. If the destination drive is blank to start with then there should be no fragmentation.
    2. If that is not an option, defragment the destination drive before starting the operation again.
    3. When formatting the destination volume use a larger allocation size. e.g. 64KB. This will reduce the number of fragments and is still efficient when dealing with a small number of large files.
    4. Enables support for large file record segments (FRS). Using the UseLargeFRS option of the Format-Volume cmdlet in Windows PowerShell. For large FRS records, the limit increases from about 1.5 million extents to about 6 million extents. See also,