[CentOS] Anaconda doesn't support raid10

Tue May 8 18:52:58 UTC 2007
Toby Bluhm <tkb at midwestinstruments.com>

Les Mikesell wrote:
> Ruslan Sivak wrote:
>> Interesting thing... I build the following set up:
>>
>> /boot on raid1
>> swap on raid0
>
> Swap on raid1 has a chance of working through a drive failure.  Raid0 
> doesn't.
>
>> / on raid6
>
> Does the installer do that?
>
>> /data on 2 lvm raid1's.
>
> If you are going to use LVM you don't have to match your partitions 
> across all 4 drives.  Put /boot, swap, / on raid1 on the 1st 2 drives 
> with another raid1 for the rest of the space.  Then make a raid1 using 
> partitions that fill your 3rd and 4th drive and combine the two large 
> raid1's in LVM.  That leaves it so you can expand if you want to add 
> more drives.
>
>> I shut down and plucked out one of the drives (3rd one I believe).  
>> Booted back up, everything was fine.  Even swap (I think).  I, 
>> rebooted, put in the old drive, hot added the partitions and 
>> everything rebuilt beautifully.  (again not sure about swap).
>>
>> I decided to run one more test.  I plucked out the first (boot) 
>> drive.  Upon reboot, I got greeted by GRUB all over the screen.  Upon 
>> booting into rescue mode, it couldn't find any partitions.  I was 
>> able to mount boot, and it let me recreate the raid1 partitions, but 
>> no luck with raid6.  This is the second time that this has happened.  
>> Am I doing' something wrong?  Seems when I pluck out the first drive, 
>> the drive letters shift (since sda is missing, sdb becomes sda, sdc 
>> becomes sdb and sdd becomes sdc).
>
> The only thing that should care about about this is grub.  Everything 
> else should autodetect.
>
>> What's the proper repair method for a raid6 in this case?  Or should 
>> I just avoid raid6, and put / on 2 an LVM of 2 raid1's? 
>
> I'd put / on one raid1 with no LVM.
Call that raid1 #0.

Put the rest of disk1 & 2 into raid1 #1 , put all of disk 3 & 4 into 
raid1 #2 , put raid1 #1 & raid1 #2 into LVM. So your LVM size should be  
something less than  (2 * disk) - OS, everything mirrored.


> And personally, I'd do the same with the rest of the space and deal 
> with the extra partition by mounting it somewhere.  LVM avoids the 
> need for that, but at the expense of no longer being able to recover 
> data from any single drive.
>




-- 
Toby Bluhm
Midwest Instruments Inc.
30825 Aurora Road Suite 100
Solon Ohio 44139
440-424-2250