[CentOS] looking for RAID 1+0 setup instructions?

Mon Aug 31 03:47:05 UTC 2009
Oliver Ransom <oliver at ransom.com.au>

On 31/08/2009, at 1:11 PM, Christopher Chan wrote:

> Miguel Medalha wrote:
>>> Can someone please assist met with some software RAID 1+0 setup
>>> instructions? I have searched the web, but couldn't find any. I  
>>> found
>>> a lot of RAID 10 setup instructions, but it doesn't help me.
>>>
>>>
>>
>> As Oliver Ransom replied to you, RAID 1+0 (not to be confused with  
>> RAID
>> 0+1) is RAID 10. mdadm has direct support for RAID 10. I am using  
>> it on
>> CentOS 5.3 and it works really well.
>>
> RAID 1+0 is NOT RAID 10. raid 1+0 is achieved using the combination of
> raid1 and raid0 personalities. Raid10 is a different animal and has  
> its
> own personality. (personality as reported by 'cat /proc/mdstat' aka md
> modules)
>
> raid10 was only introduced in 2.6.9 and Oliver's link clearly shows  
> that
> it is 'Non-standard' or not raid1+0.

RAID 10 and 1+0 are referred to interchangeably in the  
Nested_RAID_levels article, "RAID 1+0, sometimes called RAID 1&0, or  
RAID 10".

I'm a bit confused now!

>
>
>> You might be interested in this article:
>>
>> "Why is RAID 1+0 better than RAID 0+1?"
>> http://aput.net/~jheiss/raid10/
>>
>
>
> The whole raid1+0 or raid0+1 argument was really only relevant in the
> days of pata when one disk dying on one channel might take out the  
> other
> disk on the same channel or the controller. Now that we are using  
> SATA,
> it is MOOT.
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