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What will happen if i try to restore the partition table of a larger hard disk to smaller hard disk, for example: partition table of 250GB hard disk to a 80GB hard disk using sfdisk like this.

sfdisk /dev/sda < PartitionTable250.txt

Will sfdisk detect it?

I think there will be no problem if the partition table of a smaller hard disk is going to be restored on a larger hard disk?

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up vote 1 down vote accepted

You will probably end up creating an invalid partition table.

I've never tried this, but here's what I expect:

  • sfdisk should write the partition table to the device. This will succeed, because the primary partition table is contained within the MBR (sector 0 of the drive), and any extended partition table is contained nearby.
    (I believe, but am not sure, the extended partition table is stored within the first 63 sectors of the drive -- the first partition normally starts at sector 63. Remember that the 4 primary partitions (or 3 primaries and 1 extended) are all contained within the primary partition table in the MBR.)

  • Any partitions in the table that exist wholly within the first 80GB will work fine.

  • Any partitions in the table that exist partially or wholly beyond the first 80GB will not work. Simply put, the table will refer to sectors that do not exist on that device.

You're generally correct in that a smaller drive's partition table restored onto a larger drive should not have a problem.

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+1 don't do that. – David Mackintosh Mar 24 '10 at 16:48

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