My Fedora system has two (identical, but that doesn't matter) disk drives.
Fedora is installed on /dev/sdb which uses LVM. Currently /dev/sda is partitioned the 'old fashioned' way. Now that I'm happy with the Fedora installation I want to tidy things up and use LVM for /dev/sda as well.
Backing up and copying the data across is straightforward enough, I can cope with that. I have enough space that I can empty /dev/sda completely and partition it from scratch.
However what worries me slightly is that there is presumably an MBR (that's what DOS used to call it) on /dev/sda which the BIOS goes to when the system is powered up. If I repartition /dev/sda will I lose this boot record? How does this get created in the Linux way of doing things?
Chris G wrote:
However what worries me slightly is that there is presumably an MBR (that's what DOS used to call it) on /dev/sda which the BIOS goes to when the system is powered up. If I repartition /dev/sda will I lose this boot record? How does this get created in the Linux way of doing things?
Which bootloader are you using? Usually grub, which would mean: grub_install /dev/sda Lilo, just rerun. And there should be a backup in /boot/boot_mbr (or something like that) which you could dd if=/boot/boot_mbr of=/dev/sda but only if everything else fails and your data's safe on another drive.
On Mon, Nov 05, 2007 at 10:01:02AM +0000, Bill Hill wrote:
Chris G wrote:
However what worries me slightly is that there is presumably an MBR (that's what DOS used to call it) on /dev/sda which the BIOS goes to when the system is powered up. If I repartition /dev/sda will I lose this boot record? How does this get created in the Linux way of doing things?
Which bootloader are you using? Usually grub, which would mean: grub_install /dev/sda
But.....
My existing Fedora installation (using grub as you say) is on /dev/sdb with /dev/sdb1 being mounted as /boot for grub etc.
So if I (say) completely repartitioned and reformatted /dev/sda would I lose the MBR that tells the system to boot from /boot on /dev/sdb? If it wouldn't reboot then I can't run grub.
... and wouldn't "grub-install /dev/sda" expect a boot partition or something on /dev/sda, there might not be one.
Lilo, just rerun. And there should be a backup in /boot/boot_mbr (or something like that) which you could dd if=/boot/boot_mbr of=/dev/sda but only if everything else fails and your data's safe on another drive.
None of the documentation I can find tells how the MBR relates to the rest of the boot process if it's on a different drive.
On 05/11/2007, Chris G cl@isbd.net wrote:
On Mon, Nov 05, 2007 at 10:01:02AM +0000, Bill Hill wrote:
Chris G wrote:
However what worries me slightly is that there is presumably an MBR (that's what DOS used to call it) on /dev/sda which the BIOS goes to when the system is powered up. If I repartition /dev/sda will I lose this boot record? How does this get created in the Linux way of doing things?
So if I (say) completely repartitioned and reformatted /dev/sda would I lose the MBR that tells the system to boot from /boot on /dev/sdb? If it wouldn't reboot then I can't run grub.
Which is why you use a live-cd. Boot it, and either reinstall your bootloader using files and config from existing system, or use a liveCD to boot your existing sytem (not the CD system) and then re-run your bootloader command. This works really well for LILO.
Srdjan
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Bill Hill -
Chris G -
Srdjan Todorovic