Flash Drive Backup

  • Running a full install on usb flash drive.  Obviously at some point the usb flash drive will exceed write wear and die.  So keeping a duplicate of the active one for when that happens.

    Is this a good way to make a backup of the active usb flash drive?  Or is there a better way?

    dd if=/dev/da0 of=/dev/null bs=1m    # Check for Error
    dd if=/dev/da0 of=/dev/da1 bs=1m    # Copy Flash Drive Image

  • I do a similar thing to backup a 1GB solid state disk module to another.

    dd reads and writes bypass the file system so I don't think the second sync does anything particularly useful.

    I have seen errors reported on some flash drives when using "large" block sizes. I suppose the optimum block size would be the flash drive page size but I don't know a generic way of finding that out.

    I have been running pfSense full install on a Transcend 1GB solid state disk module for over 3 years without problem. But such modules are intended to be disk replacements unlike common USB flash drives which are intended for "read man, write few" applications.

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