bios boot part on 2 disks

[bouchemp]

Apologies if this has already been covered; if it has I couldn't find it. First and foremost, this question does NOT pertain to a dual-boot system. I wish to set up a F16 system which uses GPT partitioning and needs a bios boot partition. I have two identical HDD's that will be set up as RAID 1 using software RAID. If I create a bios boot partition on both drives, will the boot loader info be installed on both? My BIOS will allow booting from several (more than 3) devices. I'm thinking (hoping) that if a drive fails, and if there's a bios boot part on both drives, AND since the drives were mirrored, the system will boot with little or no intervention. Any info would be appreciated.

[george_toolan]

Are the drives larger than 2 TiB? Linux may still have some issues booting in UEFI mode.

With RAID 1 the second drive is automagically mirrored. You will only see one drive and you only have to create the partitions once.

[bouchemp]

The drives in question are only 160GB. This is an older mobo hence the need for a 'bios boot' partition. I've been through the install and set the drives up thus:

sda1 - bios boot
sda2 - swap
sda3 - raid part
sda4 - raid part

sdb - ditto

I then set up RAID 1 as such

md0 - sda3 sdb3 - ext4 - /boot
md1 - sda4 sdb4 - LVM

I don't think the 'bios boot' partition can (should?) be RAID'd (correct me if I'm wrong). Also, the installer only allows the boot blocks to be installed in the MBR of one drive. I either need to figure out a way to install boot blocks to the MBR's of both drives or install the boot blocks on md0 (that is an option). Don't know the ramifications of that. Please pardon my ignorance and thanks for you suggestions.

[DBelton]

Actually, it would depend upon what type of RAID you are using.

If you have a hardware RAID controller, then it would mirror the drives automatically.

If you are using linux software RAID, then it won't mirror the bios_boot partition since those partitions don't actually get mounted.

You would need to manually mirror the bios_boot partition and banually install the bootloader onto the second drive if you are using software RAID.

You can use grub2-install to put it onto the other drive.

You could do this:

grub2-install /dev/sda
grub2-install /dev/sdb

That would put the bootloader onto both drives, and you could set you BIOS to boot from either one.

Edit:

The installer will only put the bootloader onto one drive. You go back and manually install the bootloader ot both drives after the install is finished. You can do it once you have your system booted up and running.

[bouchemp]

Thanks, DB. I'm using software RAID (too cheap to buy hardware RAID and have some problems with FakeRAID). I'll give the grub2_install /dev/sd[ab] a try. I'm wondering; should I do this periodically to keep things sycn'd up? Or, if there's an update to grub2? It shouldn't hurt anything.

[DBelton]

The way things are currently, if there is an update to grub2, it doesn't automatically update the bootloader installed. You need to manually re-install it anyway. You just do 2 instead of 1

There really isn't a need to update it periodically, though. Once installed, it pretty much remains the same until you reinstall it (in case of an update, etc...)

But, no, it wouldn't hurt to periodically update them, though.

A lot (most) people don't realize that a normal update to grub2 doesn't update the installed bootloader on their system, and never go back and re-install the bootloader code, so are running with the same bootloader than was put there during the install.

[bouchemp]

Good information. This will increase the resiliency of my home server. Thanks again. Of note, I'm an old Solaris hack and am used to using SVM mirrored drives.