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

Christopher Chan christopher.chan at bradbury.edu.hk
Mon Aug 31 03:41:04 UTC 2009

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 

raid10 was only introduced in 2.6.9 and Oliver's link clearly shows that 
it is 'Non-standard' or not raid1+0.

> 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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