Always recommended that you should take backup MBR.
It is hard disk partition table on your server.
We can use dd command to take a backup for MBR.
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[root@~]# dd if=/dev/hdX of=/tmp/hda-mbr.bin bs=512 count=1
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Replace X with the actual device name. ex. /dev/hda or /dev/sda
In order to restore it back on the server, use following command
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[root@~]# dd if= hda-mbr.bin of=/hev/hdX bs=1 count=64 skip=446 seek=446
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