Re: issue with mdadm and mirroring drives
19/01/2012 00:03, Joey L wrote:
> Sorry - just a couple of last things:
>
>
> 1. do i run the command - "grub-install --recheck --no-floppy
> /dev/sdc1" and "grub-install --recheck --no-floppy /dev/sdd1" ???
>
> or do I run it on the whole drive meaning - "grub-install --recheck
> --no-floppy /dev/sdc" and "grub-install --recheck --no-floppy
> /dev/sdd"
Whole drive, like "/dev/sdd", unless you really know what you are doing
and want to install to a partition instead (typically if you have
another os in multiboot that manages the bootloader).
> Is that creating a boot sector ? what is it really doing ? do i need
> to set something active in the boot partition - meaning in fdisk ?
Usually no for Linux, the "boot" flag is for the /boot partition where
the kernel resides.
grub2 (aka grub-pc) support special "bios_grub" partition, but that's
meant for gpt disklabel and is completely irrelevant for you.
Grub is installed in the Master Boot Record ("MBR" for short), and some
components in the free space between the MBR and the start of the first
partition. You don't have to worry about this unless something is going
seriously wrong during the grub installation process.
>
> 2. update-initramfs -u -k all -this command only update /boot dir ?
> and then the mirroing copied to the other drive ??
>
> 3. Big thanks for your help!
>
It update the initial ram disk (aka initrd or initramfs) that normally
resides in /boot.
Once the raid is running you don't have to worry about what's synced
anymore, everything written to the raid array is synced. At the user
level there is only one device (the raid device "md*"), only the kernel
and mdadm have to know about the physical drives.
grub deals with the drives directly, before raid is even started, that's
why you have to use the devices addresses and not the partitions.
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