Boot sequence stops at "Grub"

[OralDeckard]

I installed F8 on a drive on the IDE-Slave connector with Grub installed on the /boot partition, booted it and updated all the files, set the drive labeling to /boot1, /home1, /1 and rebooted and verified that all was well.

Then I disconnected it and connected another drive to the IDE-Master connector, installed F8 with Grub installed on the /boot partition, rebooted, updated all files, set the labeling to /boot2, /home2, /2 and rebooted again to verify that all was well.

Then I reconnected the slave, booted the master and set its grub.conf to dual boot the two. Booting from the master I can boot either drive just fine.

But now when I disconnect the master and boot from the slave, it gets only as far as putting the word "Grub" on the screen and hangs.

I did notihng to this drive from the last time it booted fine.

On the chance that it had screwed up either the MBR or the grub loader I backed up both for both drives, then copied the first 446 bytes of the Master's MBR onto the slave, then, that getting the same "Grub" thing, copied the first 512 bytes of the master's boot partition sector onto the slave. That too failed, so I copied the slaves sectors back.

So,

Does anyone have any idea why the boot sequence would stop at "Grub", or what I might try to get the slave drive to boot on its own again ? Or any idea what might have happened to it go get this kind of result?

Any help will be very much appreciated.

[stoat]

Originally Posted by OralDeckard

Does anyone have any idea why the boot sequence would stop at "Grub"...

Hello OralDeckard,

It stops like that with "GRUB _" on the screen with the underline blinking and the system frozen when the next stage cannot be found for various reasons.

Originally Posted by OralDeckard

I installed F8 on a drive on the IDE-Slave connector with Grub installed on the /boot partition...

Originally Posted by OralDeckard

Then I disconnected it and connected another drive to the IDE-Master connector, installed F8 with Grub installed on the /boot partition...

Did you say those right? Because if both systems had GRUB installed in the boot partition, then something else not mentioned has to be booting them. See what I mean? The typical Fedora boot sequence is like this...

                                         grub.conf              kernel 1
                                             |                 / 
BIOS -->  MBR   -->    stage1.5     -->   stage2  --> GRUB Menu 
        (stage1)   (DOS Compat Area)   (/boot/grub)            \ 
                                                                kernel 2

This is what you seem to be describing for both systems (which is fine if something else will be booting them)...

                                         grub.conf              kernel 1   
                                             |                 /
BIOS -->  MBR   ???      stage1    -->    stage2  --> GRUB Menu
          (?)          (1st sector     (/boot/grub)            \ 
                        of /boot)                               kernel 2

So if you really did install stage1 in the boot partitions of both systems, then there is no stage1.5 and booting goes directly from stage1 in the boot sector to stage2 in the filesystem. But what is in the MBR to continue the bootstrapping process to stage1 in the boot sector of either system mentioned? It's something not mentioned yet (a third Linux system's boot loader, NTLoader, a boot disk, etc.)

And if you reinstalled GRUB in a master boot record (or anywhere, really) later, that is what likely broke the other system. For example, reinstalling GRUB to anywhere (including a floppy) using grub-install will rewrite the stage files in /boot/grub breaking whatever booting arrangement existed before. That's okay because we usually want it broken, want the new arrangement, and don't intend to unplug things afterwards.

Reinstalling GRUB is usually indicated for the "GRUB _" thing. And probably reinstalling GRUB will fix your busted "slave" system, but I don't understand what really happened yet and have no specific advice on how to do it without breaking something else.

[OralDeckard]

Thank you for your help Stoat.
First let me say that I did get the problem solved. Everything seemed to point to a bad grub loader, regardless that I had replaced the first 512 bytes of the boot partition with a known good sector. So I backed up both boot partitions, and the slave's grub.conf separately, then copied the master's whole boot partition over the slave's, re-labeled the new slave to /boot2 and copied its original grub.conf back into it. It then booted like a charm. I can now boot either drive independent of the other.

But if you have time I'd like to pick your brain a little.

Originally Posted by stoat

Hello OralDeckard,

Did you say those right? Because if both systems had GRUB installed in the boot partition, then something else not mentioned has to be booting them.

Yes, I said those right. I was careful to make sure the grub installer went onto the first sector of the boot partition, and not onto the MBR.

Originally Posted by stoat

See what I mean? The typical Fedora boot sequence is like this...

                                         grub.conf              kernel 1
                                             |                 / 
BIOS -->  MBR   -->    stage1.5     -->   stage2  --> GRUB Menu 
        (stage1)   (DOS Compat Area)   (/boot/grub)            \ 
                                                                kernel 2

This is what you seem to be describing for both systems (which is fine if something else will be booting them)...

                                         grub.conf              kernel 1   
                                             |                 /
BIOS -->  MBR   ???      stage1    -->    stage2  --> GRUB Menu
          (?)          (1st sector     (/boot/grub)            \ 
                        of /boot)                               kernel 2

No, nothing else is booting them.

So as I understand what you are saying, at least one drive must have its boot loader on the MBR. So if I selected the boot partition instead of the MBR during installation, I shoud be unable to boot.

If such an arrangement were true, wouldn't that create a lot of disasters, as there is offered during installation an option that is guaranteed to cause a boot failure? I mean, if it can't boot when grub is installed in the boot partition, why offer the option?

I may not understand this as well as I should, but I was under the impression that bios passed the sequence to the first bootable drive's MBR, which, though it didn't get the grub loader, was left with the location of the boot partition that did, so no other boot device would be necessary.

What I would really like to know is, why does Fedora assume that there should be only one bootable drive in the system ? Like, there is but one Washington, and there is but one LIncoln, and there is but one Popey, and there is but one grub loader.

The reason I detatch all but the drive getting the installation is that Fedora insists on putting the grub laoder on the wrong drive. If doesn't offer a option. It just says it is instaling the grub loader on sdb. Now that would leave the drive getting the installation totally dependent upon the other drive to boot. So if the other drive died, this one would be down as well.

Maybe there is something fundamental I am missing here but that appears like a preposterous situation. As I set them up, either drive can die and I can yawn and keep on running. I can pull either drive out and install it in another machine and boot up. Way is it necessary to do an end run around Anaconda in order to have a reliable, flexible system ?

Originally Posted by stoat

And if you reinstalled GRUB in a master boot record (or anywhere, really) later, that is what likely broke the other system.

Nope. Didn't do it.

Originally Posted by stoat

Reinstalling GRUB is usually indicated for the "GRUB _" thing. And probably reinstalling GRUB will fix your busted "slave" system, but I don't understand what really happened yet and have no specific advice on how to do it without breaking something else.

I appreciate that. I don't know what happened to it. As I said, I didn't do anything to it between the time when it booted find and when it failed, other than mount it on the other drive's file system and set up dual booting for it. That was things I did to the master drive, and should have left the slave unaffected. It was probably just a random corruption.

I did it like I have many times in the past. But when it wouldn't respond to anything that made sense I decided to ask for help. And logical help can only be provided for a logical event. Replacing the boot partition was a shotgun approach that just happened to take in the problem, which was "somewhere" in the a the partition that corrpted for no apparent reason.

But though my approach seems straight forward to me, it does appear to be non-standard, because Anaconda provides no option to put the grub loader in the drive getting the installation unless all preposterous options are detached. I really would like to know why.

[stoat]

Originally Posted by OralDeckard

...I was under the impression that bios passed the sequence to the first bootable drive's MBR, which, though it didn't get the grub loader, was left with the location of the boot partition that did, so no other boot device would be necessary.

Hello again OralDeckard,

I think you understand that correctly. That is actually a good way to boot Fedora. I didn't even think about that in this case because that is the MS way of booting (BIOS=>MBR code=>Active partition boot sector code=>...=>kernel), and Windows was never mentioned here. Sorry. Installing GRUB stage1 in the Fedora boot sector, marking that partition active, and booting with MS boot code in the MBR will result in Fedora booting. It's not talked about a lot here, but people do it. And as you correctly did, you cannot allow Fedora to install GRUB in the MBR or that scheme will be busted.

As you know, GRUB boots in stages, each of which knowing where the next stage is located. Active partitions are never involved. That's actually why it is so easy to install Fedora in a logical partition, but a little more complex to install, say, XP there. Logical partitions cannot be made active, and an active primary is then required just to hold XP's boot loader files. Your Fedora booting method is a smart way to do business (IMO) but has that one same limitation: the boot partition cannot be a logical partition.

[OralDeckard]

Thank you Stoat. I'm glad to know my method isn't so strange as to be heretical But why is the preferred Fedora method one that doesn't allow more than one bootable drive in a system ? I maintain very reliable systems at work because if one OS FODs, either Linux or Windows, I can fix it at my leasure AFTER rebooting into the alternate OS. And that's something that just can't be done if only one drive can be bootable. Why would anyone prefer that? There may be a very good reason that I would jump at if I just had an idea what it was.

I mean, I see a lot of greif on the forums from people who's Linux quits booting, and they are trying to figure out some way to get as far as a level three boot to command line, or booting with a live CD, or rescue disk. But when I have that problem, as in this case, I just boot the other drive and use it to fix the first one, run level 5. Hey, the OS is free right? Why limit myself to just one ? In fact, "the server" is never down at work, because there are two who's identities can be swapped in a minute, and both of which have two bootable drives.

Yet when I go to install Fedora I have to disconnect all other drives so it is forced to put the grub loader on the correct drive. What they hey ?

[stoat]

Originally Posted by OralDeckard

The reason I detatch all but the drive getting the installation is that Fedora insists on putting the grub laoder on the wrong drive. If doesn't offer a option. It just says it is instaling the grub loader on sdb. Now that would leave the drive getting the installation totally dependent upon the other drive to boot.

Hello again OralDeckard,

Maybe you don't have to unplug the other drives. Regarding your current preferred Fedora booting method (shall we name it the "active partition method"?), Fedora always offers the option to install GRUB in the first sector of the boot partition of the Fedora system being installed. I think you will agree to that. No problems for you there. It will probably even make that boot partition the active partition. So, you don't really have to unplug other drives for that booting method.

But it's that MBR option that irritates you. No? Fedora by default always wants to install GRUB on the drive that is first in the BIOS boot order which may not be what you want for that "boot any drive in the system" capability that is important to you. Right? But are you familiar with the Change Drive Order button in the Configure advanced boot loader options page? Clicking that button during installation will present a list of your drives in BIOS boot order. You can move to first in the list (at the top) the drive whose MBR you would prefer to have GRUB. Continue on and then you will see indications that GRUB will be installed in the MBR of that drive. You can use this anaconda feature to install GRUB in the MBR of the drive with the system being installed even it is not really first in the BIOS boot order. Then, let's say you did that to two drives (those two in your first post), you could then boot the either one by changing the BIOS boot order, or more conveniently, by using the configfile menu command in the "main" system's grub.conf. Are you familiar with configfile GRUB menu command? Using that in grub.conf can boot another Linux by launching its grub.conf bringing up its menu. It's especially neat because updating the kernel of that system does not break it. So even when choosing to install GRUB in the MBR, you don't really need to unplug drives for that either.

If you knew all that, and I am missing your point. I apologize. But it sounds like a potential answer to your complaint about anaconda and GRUB at installation time. Maybe. It's not necessarily any better than your "active partition method", but it might redeem anaconda in some little way for you.

[OralDeckard]

Thank you Stoat. You just gave me a tremendous new power

I shut down a system, disconnected all droves, then attached two guiny pig drives.
I then proceeded to install F8 on the slave drive (sdb).

And when I got to the grub installer screen it gave me two options:
O The GRUB boot loader will be installed on /dev/sda.

O No boot loader will be installed.

This is where I learned when I first started with Linux to not have another drive attached. At that time I avoided advanced options. And now, looking for advanced options, I guess not seeing that one was an ingrained habit.

Again, thank you very much