[CentOS] Re: Please help! boot problem
Scott Silva
ssilva at sgvwater.com
Mon May 1 20:31:06 UTC 2006
ssilva<at>sgvwater<dot>com
obscured to thwart spam harvesters, of course
Mace Eliason spake the following on 5/1/2006 2:09 PM:
> Can I email you directly to cut down on posts to the mailing list?
>
> I have changed the SCSI ids on the two hard drives and now it will boot
> from the damaged drive. Still won't boot from the cd which is an ide
> cdrom and it is set to boot from cd first.
> Should I allow it to boot from the old drive with the current good drive
> hooked up as well? I am worried that it will rebuild the old info over
> the new.
>
> Thanks
>
> Scott Silva wrote:
>> Mace Eliason spake the following on 5/1/2006 1:51 PM:
>>
>>> 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
>>>
>> You will have to make sure that both drives and the cdrom if it is
>> scsi have
>> different id's.
>> To boot from cd with the drives in might need you to go into the bios
>> option
>> and change the boot order.
>> The system must let you boot from cd with both drives in, or you
>> wouldn't have
>> been able to install it in the first place.
>>
>> To fix this, you will have to get both drives in and be able to boot
>> from the
>> rescue disk.
>>
>>
>>
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