Re: Please help! boot problem

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Scott Silva wrote:
> Mace Eliason spake the following on 5/1/2006 1:27 PM:
>   
>> Scott Silva wrote:
>>     
>>> Mace Eliason spake the following on 5/1/2006 12:55 PM:
>>>  
>>>       
>>>> Scott Silva wrote:
>>>>    
>>>>         
>>>>> Mace Eliason spake the following on 5/1/2006 12:29 PM:
>>>>>  
>>>>>      
>>>>>           
>>>>>> Scott Silva wrote:
>>>>>>           
>>>>>>             
>>>>>>> Mace Eliason spake the following on 5/1/2006 12:13 PM:
>>>>>>>  
>>>>>>>               
>>>>>>>               
>>>>>>>> So from what I have read I would run grub-install /dev/sda ?
>>>>>>>>
>>>>>>>> I have setup the raid with
>>>>>>>> /boot (100Meg)
>>>>>>>> /swap (2gig)
>>>>>>>> / (the rest)
>>>>>>>>
>>>>>>>> All 3 are mirrored.
>>>>>>>>
>>>>>>>> I don't want to mess this up sorry I am new to this.
>>>>>>>>
>>>>>>>> Mace
>>>>>>>>
>>>>>>>> Scott Silva wrote:
>>>>>>>>                      
>>>>>>>>                 
>>>>>>>>> Mace Eliason spake the following on 5/1/2006 10:58 AM:
>>>>>>>>>  
>>>>>>>>>                            
>>>>>>>>>                   
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> I have a setup with raid 1 and one drive has failed, and the other
>>>>>>>>>> drive
>>>>>>>>>> won't boot says missing os.
>>>>>>>>>>
>>>>>>>>>> I thought I had it setup and tested but it would appear that it
>>>>>>>>>> wasn't
>>>>>>>>>> setup to boot form either drive.
>>>>>>>>>>
>>>>>>>>>> How can I boot from the good drive that is missing the grub.
>>>>>>>>>>
>>>>>>>>>> I am thinking of using linux rescue when booting from the
>>>>>>>>>> centos 4.2
>>>>>>>>>> disc
>>>>>>>>>>
>>>>>>>>>> This is a production machine and I don't want to mess it up.
>>>>>>>>>>
>>>>>>>>>> Please help
>>>>>>>>>>                                         
>>>>>>>>>>                     
>>>>>>>>> Use linux rescue and you can fix grub.
>>>>>>>>> http://www.gnu.org/software/grub/manual/html_node/Invoking-grub-install.html
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>  
>>>>>>>>>                               
>>>>>>>>>                   
>>>>>>> less /boot/grub/grub.conf and post please-- just to be careful.
>>>>>>>
>>>>>>> Okay I have booted with linux rescue and skiped the network setup,
>>>>>>> and
>>>>>>> skiped the next part and gone right to the shell.
>>>>>>>                   
>>>>>>>               
>>>>>> If I type grub-install it says no such file or directory.
>>>>>>
>>>>>> I tried less /boot/grub/grub.conf same thing.
>>>>>>
>>>>>> I did boot with the centos cd as if I was installing and used manual
>>>>>> partion to see if the partions where still there and they are.
>>>>>>
>>>>>> No sure what to do now.  I will try and search for  grub-install. 
>>>>>> I am
>>>>>> assuming that I am searching the cd?
>>>>>>
>>>>>> Mace
>>>>>>             
>>>>>>             
>>>>> You can't skip the part about mounting your existing system. You will
>>>>> need to
>>>>> do that, and after it mounts, run chroot /mnt/sysconfig.
>>>>> That should make all the commands run on YOUR files instead of the
>>>>> bootdisks
>>>>> running system.
>>>>>
>>>>>         
>>>>>           
>>>> Okay I didn't skip this time and it did a search and says "You don't
>>>> have any Linux partitions. Press return to get a shell. The system will
>>>> reboot automatically when you exit from the shell."
>>>>
>>>> What the?
>>>>
>>>> If I goto the shell and run fsdisk /dev/sda it shows I have 3 partitions
>>>> with /boot set for booting.
>>>>
>>>> I do get that?
>>>>     
>>>>         
>>> If you show a /boot partition you don't have software raid.
>>> The partitions in software raid are type fd (linux raid).
>>> Does the replaced drive show up?
>>>
>>> With a scsi drive, the lowest number addressed drive in the chain will
>>> be sda.
>>> So if you had an sda set as device id 0, and an sdb set as device id
>>> 1, and
>>> removed the sda drive, what was sdb would now show up as sda. Scsi
>>> doesn't
>>> have fixed addresses like ide.
>>> If you had proper software raid, your partitons would be all of typd
>>> fd, and
>>> you should have a matching set on each drive ( sda1 and sdb1 would
>>> both be
>>> type fd and the same size ,etc...).
>>>   
>>>       
>> Okay to clarify
>>
>> I have only hooked up the drive that is not bootable.  The drive that is
>> bootable has been disconnected.
>>
>> If I run sfdisk on the nonbootable drive I get
>> /dev/sda1  (id fd linux raid autodetect) marked * for boot
>> /dev/sda2   "   "
>> /dev/sda3   "   "
>>
>> So yes it is software raid am I right.  The system has been running off
>> this drive for almost a month, until someone rebooted the server.
>>
>> Should I have both drives installed when I run the linux rescue?  I know
>> the one drive will boot now that I fixed it but the info on it is amost
>> a month old.  I really need the info from the drive that is not
>> bootable.  Last time I tried to boot with both drives installed it
>> didn't it gave a no boot partition error.
>>
>> Does linux automatically rebuild the raid when it boot?  If I do get
>> them to boot with the good drive I don't want it to over write the
>> current drive.
>>
>> Thanks  you have been alot of help so far.
>>     
>>>   
>>>       
> Then the other drives partition table has been changed. You will need to have
> both drives in to repair the system. If you just want to get booting, you can
> swap the drives scsi id's so the good drive is the lower numbered drive. Then
> you can use the rescue disk to get the system running.
> After you boot with both drives in with the rescue cd, try the option to look
> for linux systems. Make sure that you see both drives, and lets see the
> partition info from both, again just to be safe.
> I don't want to give you some commands that will cause damage.
>
>
>   
As it is if I hook up both drives and not change the scsi ids it won't 
boot.  It won't even boot from cd either.  Says missing partition boot 
sector.

Mace

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