[clug-talk] moving raid drives?

Martin Glazer linux at glazer.ca
Thu Jul 23 17:06:22 PDT 2009



Gustin Johnson wrote:
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>
> Martin Glazer wrote:
>   
>> <snip>
>>     
>>>> Using CentOS 5.2 and in the fstab, the drives are referenced via 
>>>> /dev/md2, /dev/md0, etc and not via UUID. In mdadm.conf they are
>>>> referenced via UUID
>>>>
>>>>     
>>>>         
>>> The UUID should be the same, but it is worth checking the UUIDs in the
>>> mdadm.conf against what the (live) OS is actually seeing.  These are
>>> symlinks in /dev/disk/by-uuid btw.
>>>
>>>   
>>>       
>> Now I'm confused about the UUID - when I recreate the arrays on the live
>> cd, I get different UUID's than what is in the mdadm.conf file when
>> compared to the /dev/disk/by-uuid
>> (I also found that blkid gives the UUID information)
>>
>>
>> If I do a mdadm --examine --scan
>> I get the same UUID's that are in the mdadm.conf file.
>>
>> So which is correct?
>> If the ones under the live CD, should I change the mdadm.conf file to match?
>>
>>     
> I am not sure.  I always layer LVM on top of the software RAID stack, so
> I just use the UUID of the LVM.
>
> How far along the boot process does it get before panicking?  What is
> the last thing you see before the panic?  You may need to edit the grub
> kernel line and remove the quiet option (this can be done within grub,
> no need to boot and mount by using the "e" key while in grub).
>   

these are the last few lines before crashing

Red Hat nash version5.1.19.6 starting
Unable to access resume device (/dev/md1)
EXT3-fs: unable to read superblock
mount: error mounting /dev/root on /sysroot as ext3:
setuproot: moving /dev failed: No such file or directory
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!


> I am not sure what the option "rhgb" is for, that is a new one for me.
>   

I think it has something to do with the Red Hat graphical boot...


> <snip>
>   
>>> If you can mount the arrays and read data then there is nothing wrong
>>> with the arrays themselves.  Chances are this is a grub problem.  What
>>> is the default entry in /boot/grub/menu.lst?
>>>   
>>>       
>> Not sure that it is a grub problem though -
>>
>> This is the default entry
>> title CentOS (2.6.18-92.1.22.el5)
>>         root (hd0,0)
>>         kernel /vmlinuz-2.6.18-92.1.22.el5 ro root=/dev/md2 rhgb quiet
>>         initrd /initrd-2.6.18-92.1.22.el5.img
>>
>>
>> I also recreated initrd in a chroot in case I needed different modules
>> on boot as per Cody's message earlier.
>>
>> <snip>
>>     
>>> I would verify the partitions with fsck.  Of course they should not be
>>> mounted when you do this.
>>>
>>>   
>>>       
>> They all check out okay
>>
>>     
> What is the difference between the old server and the new?
>   

The old server has a different systemboard. Both Intel, but the one I am 
trying to install the drives onto is older.


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