[CentOS] Re: Please help! boot problem
Mace Eliason
meliason at shaw.ca
Mon May 1 22:37:55 UTC 2006
Thanks for your help, I am sure your busy doing other things as well.
As I stated in previous postings I have changed the scsi ids and now
with the two drives attached it will boot from the old drive (I am
assuming it is the old drive because the other drive would'nt boot on
its own.
If I do boot to centos now will it rebuild the mirror from the booting
drive to the other drive?
I am worried about haveing the current info over written by the old info.
At this point I will settle for just getting the one drive that has the
current info booting and working.
I need to get this back into production 45min away at a police station.
:( its their email server.
Thanks for any help
Mace Eliason wrote:
> 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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