[CentOS] raid10, centos 4.x

Fri Dec 11 00:28:41 UTC 2009
Christopher Chan <christopher.chan at bradbury.edu.hk>

John R Pierce wrote:
> I just created a 4 drive mdadm --level=raid10 on a centos 4.8-ish system 
> here, and shortly thereafter remembreed I hadn't updated it in a while, 
> so i ran yum update...
> 
> while installing/updating stuff, got these errors:
> 
>       Installing: kernel                       ####################### 
> [14/69]
>     raid level raid10 (in /proc/mdstat) not recognized
>     ...
>       Installing: kernel-smp                   ####################### 
> [19/69]
>     raid level raid10 (in /proc/mdstat) not recognized
> 
> 
> is this a problem?   the raid10 'seems' to work....
> 

If anaconda is doing the update here, I guess it is because anaconda in 
4.x does not have raid10 personality support. The raid10 personality is 
NOT the same as nested raid1+0. It is an entirely new module from Neil 
Brown that has a poor choice of a name imho. It does things very 
differently from what you expect from a nested raid1+0 array.