[WBEL-users] Adding to RAID 1, only sees new partition as spare... {Scanned} {Scanned}

[Scott Silva]

Kirby C. Bohling wrote:
> On Wed, May 18, 2005 at 01:06:25PM -0700, Scott Silva wrote:
> 
>>Benjamin Smith wrote:
>>
>>
>>>It appears that it's simply not possible to "add" drives to a RAID 1 array. 
>>>raidreconf does not support RAID 1. 
>>>
>>>I had to start from scratch, reinitialize the array with both drives, run 
>>>mke2fs, and recopy the data back over from the original drive. It took 
>>>another 17 hours to copy everything, (ugh) but it's all up and working fine 
>>>now. 
>>>
>>>Thanks! 
>>>
>>>-Ben 
>>>
>>>On Tuesday 17 May 2005 15:15, Scott Silva wrote:
>>> 
>>>
>>>
>>>>Benjamin Smith wrote:
>>>>   
>>>>
>>>>
>>>>>I have a server that does backups, and I want to replace an existing 160 
>>>>>     
>>>>>
>>>
>>>GB 
>>> 
>>>
>>>
>>>>>drive, with a RAID 1 300 GB array. 
>>>>>
>>>>>I don't have enough IDE slots to mount all at the same time. So, I 
>>>>>     
>>>>>
>>>
>>>installed a 
>>> 
>>>
>>>
>>>>>single 300 GB HDD, configured it as /dev/md0 RAID 1, made a filesystem, 
>>>>>mounted, and copied all the data over. It's seen and mounts fine with all 
>>>>>data present. 
>>>>>
>>>>>Now, I've removed the original 160 GB HDD, and put the other new 300 GB in 
>>>>>it's place. 
>>>>>
>>>>>I've tried and tried, and I can't get the 2nd 300 GB drive to sync up to 
>>>>>     
>>>>>
>>>
>>>the 
>>> 
>>>
>>>
>>>>>first 300 GB drive. It keeps seeing it as a spare... 
>>>>>
>>>>>What am I missing? 
>>>>>
>>>>>1st 300 GB partn in array (with data on it) /dev/hdh1 
>>>>>2nd 300 GB partn in array (seen as spare) /dev/hde1 
>>>>>     
>>>>>
>>>>
>>>>Did you properly partition the new drive as type fd (linux raid)?
>>>>
>>>>Maybe you should use mdadm. I have had better luck with it over raidtools.
>>>>you would use ;
>>>>
>>>>sfdisk -d /dev/hdh |sfdisk /dev/hde
>>>>
>>>>to clone the partition data, then
>>>>
>>>>mdadm -a /dev/md0 /dev/hde1
>>>>
>>>>
>>>>   
>>>>
>>
>>I know you can create a raid1 array with only one drive and add the
>>other drive later, because I have done it.
>>
> 
> 
> That's really nice, show me a command that changes the number of
> devices in a RAID device.  That is the crux of your problem.
> 
> I've read that you can create a RAID device, and tell it there are
> two devices, and make one that fails immediatly (any old block
> device will do the job as long as it appears to be large enough).
> It will write the meta-data to the first block device so it looks
> like it has two devices.  (Essentially, you are creating a mirror
> with a device that fails immediatly, and then adding a new device
> later).
> 
> I've never seen anyone actually do it.
> 
> 	Thanks,
> 		Kirby

mdadm --create /dev/md1 --level=raid1 --raid-devices=2 /dev/sda1 missing
would create a 2 drive array with only one drive present.
Later you could add the second drive with mdadm -a /dev/md1 /dev/hdc1 or
whatever drive you wanted to add.




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