The secret is in the booting section. You must make sure that drive you are installing openSUSE on to is listed as the first hard drive. The drive order, for the third drive might say: sdc, sda, sdb where sdc is the hard drive you are installing openSUSE on to. You normally want to install generic boot code to the MBR, install openSUSE root folder as primary partition 1, 2, 3 or 4 AND mark it as active for booting. All of these options (except for the partition setup you create first) is located in the booting section. Here is more on partitioning:
Each hard drive can have up to four PRIMARY partitions, any of which could be marked active and bootable. No matter what you might hear, only one of the first four primary partitions can be booted from. That means you can boot from Primary partitions 1, 2, 3 or 4 and that is all. In order to boot openSUSE, you must load openSUSE and the grub boot loader into one of the first four partitions. Or, your second choice is to load the grub boot loader into the MBR (Master Boot Record) at the start of the disk. The MBR can be blank, like a new disk, it can contain a Windows partition booting code or generic booting code to boot the active partition 1, 2, 3, or 4. Or, as stated before, it can contain the grub boot loader. Why load grub into the MBR then? You do this so that you can “boot” openSUSE from a logical partition, numbered 5 or higher, which is not normally possible. In order to have more than four partitions, one of them (and only one can be assigned as extended) must be a extended partition. It is called an Extended Primary Partition, a container partition, it can be any one of the first four and it can contain one or more logical partitions within. Anytime you see partition numbers 5, 6 or higher for instance, they can only occur inside of the one and only Extended Primary partition you could have.
What does openSUSE want as far as partitions? It needs at minimum a SWAP partition and a “/” partition where all of your software is loaded. Further, it is recommended you create a separate /home partition, which makes it easier to upgrade or reload openSUSE without losing all of your settings. So, that is three more partitions you must add to what you have now. What must you do to load and boot openSUSE from an external hard drive? Number one, you must be able to select your external hard drive as the boot drive in your BIOS setup. Number two, you need to make sure that the external hard drive (or second or third internal), perhaps /dev/sdc, is listed as the first hard drive in your grub device.map file and listed as drive hd0. I always suggest that you do not load grub into the MBR, but rather into the openSUSE “/” root primary partition which means a primary number of 1, 2, 3 or 4. If number one is used, then that will be out. You will mark the openSUSE partition as active for booting and finally you must load generic booting code into the MBR so that it will boot the openSUSE partition. I suggest a partition like this:
- /dev/sdc, Load MBR with generic booting code
- /dev/sdc1, Primary SWAP (4 GB)
- /dev/sdc2, Primary EXT4 “/” openSUSE Partition Marked Active for booting (80-120 GB)
- /dev/sdc3, Primary EXT4 “/home” Your main home directory (Rest of the disk)
Thank You,