Help with boot0

Henrik W Lund henrik.w.lund at broadpark.no
Sun Nov 14 13:24:50 GMT 2004


Jay O'Brien wrote:
> Thanks Henrik and Ruben, Good input from you both. 
> 
> To be sure which HD I'm on, I made (empty) directories in the root 
> of each drive, called (either) ..AD0 or ..AD1. In this way the HD's 
> aren't completely identical, and I can see which one boots. 
> 
> I agree that boot0 shouldn't be on the second drive and I fixed that. 
> However, I couldn't restore the standard mbr until I went to 
> /stand/sysinstall, selected Configure, selected fdisk, ad1, set 
> bootable, write changes, yes, standard mbr, ok. This worked fine.
> 
> If I interrupt the boot process, at the command prompt I can use the 
> ls command to list files and see the empty directory that confirms 
> which drive has booted. If I boot from the second drive, ad1, then 
> fstab and other files point to ad0, not ad1, and I wind up on ad0, 
> regardless of which drive actually boots. 
> 
> It seems to me that the boot0cfg -o option should force the drive 
> in use to be referred to the boot0cfg option -b 0x80, and then the
> second drive would be used but called 0x80. This doesn't seem to be 
> the case. 
> 
> Apparently I will have to make some changes to the files on the 
> second drive so that the first drive won't be used at all when 
> the system is booted from the second drive. Which files?
> 
> To recap, I can use boot0 to boot from either HD. However, when 
> the boot is on the second HD, it still points to (and uses) the 
> first drive as if it was booted there. 
> 
> I have identical files on ad0 and ad1. I would like to be able to 
> boot from (and use the files on) either ad0 or ad1.
> 
> Help?
> 
> Jay O'Brien
> Rio Linda, CA, USA
Hmm...

Just a thought: what does /etc/fstab look like on your slave drive 
(ad1)? If all the mountpoints point to ad0 then what you are 
experiencing is quite normal.

My suggestion is that all references to ad0 in /etc/fstab on your slave 
drive be manually changed to ad1, as this does not happen automatically 
when tar-ing or dd-ing (or whatever method you used for mirroring the 
disks). Even if you did a clean install on both of the drives, you could 
still wind up with both of the fstabs pointing at ad0 depending on what 
your jumper configurations were when installing.

-- 
Henrik W Lund


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