How to Switch drives during Bootstrap

P

Peacekeeper2000

I do have an old HP Microserver Gen8. The Standard is, to boot from the first disk (drive C) in the 4 Drive Cage. So i Build in an additional ssd - which is disk5 - and Boot from an installed sd-card. In the past I used GRUB to switch to the disk5 (zfs). Now the sd-card is broken (no backup :( ) and I need to setup the boot process again. This time I want to use the full BSD bootstrap.
But it is challenging: I thought I only need boot0 and could interrupt the boot process to select a different disk.
Seems that is not working as only the sd-card is searched for the next boot steps. I’m not sure if I could switch the disks before the loader ?
I reviewed boot0cfg(), but seems that here I also can’t config boot0 to use a different disk. Also /boot.config seems to need a root fs , which is currently only available on disk5 (ada4) . So the example in boot.config() will write on ada4 and not on the boot drive (da0).
Is there any other possibility ? Or do I need to boot until the loader is coming up ?
 
Peacekeeper2000 said:
I do have an old HP Microserver Gen8. The Standard is, to boot from the first disk (drive C) in the 4 Drive Cage. So i Build in an additional ssd - which is disk5 - and Boot from an installed sd-card. In the past I used GRUB to switch to the disk5 (zfs). Now the sd-card is broken (no backup :( ) and I need to setup the boot process again. This time I want to use the full BSD bootstrap.
But it is challenging: I thought I only need boot0 and could interrupt the boot process to select a different disk.
Seems that is not working as only the sd-card is searched for the next boot steps. I’m not sure if I could switch the disks before the loader ?
I reviewed boot0cfg(), but seems that here I also can’t config boot0 to use a different disk. Also /boot.config seems to need a root fs , which is currently only available on disk5 (ada4) . So the example in boot.config() will write on ada4 and not on the boot drive (da0).
Is there any other possibility ? Or do I need to boot until the loader is coming up ?
Click to expand...
You could delete or rename /etc/fstab and then you should get a 'mountroot' prompt when you boot and then specfify the device, ie /dev/ada3s2 for example.

Just a suggestion.
 
balanga said:
You could delete or rename /etc/fstab and then you should get a 'mountroot' prompt when you boot and then specfify the device, ie /dev/ada3s2 for example.

Just a suggestion.
Click to expand...
Click to expand...
Hmm, that would be after or within the loader stage. I think there I just could advice the loader to mount a different disk as root.
I thought I could step in during one of the boot blocks and only need boot0 on the sd-card ( and not a full boot system )
Maybe I need a full boot system on the sd-card, but write /boot.config also on it. That might switch from the boot blocks on sd-card to the right disk and then execute the loader from that disk. Will give it a try….
 
T-Daemon said:
Does the machine have BIOS or UEFI?

Doesn't the server have a "Boot Menu" to choose the boot disk (to call, press F9 on HP, if I'm not mistaken )? Or set the BIOS/UEFI boot order to disk5 first in the list.
Click to expand...
It has a BIOS
Yes, it has a boot menu, but doesn’t allow to select the disk. It allows USB, Px, CD, or the first disk, which is always the first drive in the cage. I use the four drives in the cage for a Z-RAID and gave installed an addition SSD as CD ROM replacement. But there is no direct possibility to boot from the SSD.
 
Micski said:
It's a great little server. Why not just re-install it on new disks and migrate data to these?
Click to expand...
I don’t have a problem with the installed disks. It worked fine to use a small Linux on the sd-card together with GRUB. Grub then started FreeBSD from the 5th disk. Worked all very well until ILo smashed the sd-card with logs.
As I don’t remember how I had setup GRUB 10 years ago, I thought would be easier to use now boot0 as boot manager .
 
balanga said:
BIOS → boot0 → boot1 → boot2 → loader → kernel
Click to expand...
Yepp, now how it should work:
BIOS -> sd-card / boot0 -> disk5 / boot1 til kernel

It looks like the understanding of a boot manager is a bit different inside FreeBSD: boot0 can only handle over to boot blocks on the same device. At least I have not seen a cmd or better configuration that allow to call boot1 or boot2 on a different device.
This may only work with a /boot.config on the root filesystem if the sd-card - which means you will need a min-memstick img on the sd-card.

PS: the boot-only image is on a CD9660 FS and only read-only. Therefore you can’t put a
/boot.config on it
 
Peacekeeper2000 said:
PS: the boot-only image is on a CD9660 FS and only read-only. Therefore you can’t put a
/boot.config on it
Click to expand...
Putting a file on a iso wouldn't be a problem, just extract the image, add /boot.config, recreate the iso:

bsdinstall(8)
Rich (BB code): 
   BUILDING AUTOMATIC INSTALL MEDIA
     If building automatic install media, use tar to extract a release ISO:
           mkdir release-media
           tar -C release-media -xvf FreeBSD-13.0-RELEASE-amd64-disc1.iso

     Then place a script as above in etc/installerconfig

     This directory can then be used directly as an NFS root for diskless(8)
     installations or it can be rebuilt into an ISO image using the release
     scripts in /usr/src/release.  For example, on amd64:
           sh /usr/src/release/amd64/mkisoimages.sh -b '13_0_RELEASE_AMD64_CD'
           output.iso release-media
Populated /usr/src is required.
 
It’s now partial solved. I have booted a live system to access the sd-card and be able to make changes
The sd-card is under /dev/da0 accessible. My additional SSD as disk 5 (/ada4 with ada4p1(freebsd-boot), ada4p2(freebsd-swap), ada4p3 (freebsd-zfs). The zfs root pool is zroot and managed with bectl.
Bash: 
gpart destroy /dev/da0
gpart create -s GPT /dev/da0
gpart add -a 1m -s 500kb -t freebsd-boot /dev/da0
gpart bootcode -b /boot/pmbr -d /boot/gptzfsboot -i 1 /dev/da0
Booting the server will stop at the boot2 phase with:

>> FreeBSD/i386 BOOT
Default: disk-1:/boot/loader not found
boot:

Entering:
zfs:zroot/ROOT/default: will continue the boot process with the loader. So the server is up and running again.

Now I need to automate this -> which was a bit easier in legacy GRUB. I have read that /boot.config is written into an ‘a’ slice , which is not available on a GPT partition.
 
Micski said:
It's a great little server…..
Click to expand...
BTW: I would not recommend that server again: the build in ILO4 is crab. It needs regular multiple patches for security and it writes on the sd-card regardless of the setup. It is impossible to disable ILO, even when you do so in the setup (F8). It will enable itself again. In a former Gen7 server you could remove the ipmi card and get rid of this backdoor - ok, you need to walk to the server-cellar to restart. But a bit sports is always welcome
 
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