Re: raid10 on centos 5

[Ruslan Sivak <rsivak@istandfor.com>]

Guy Watkins wrote:
> } -----Original Message-----
> } From: linux-raid-owner@vger.kernel.org [mailto:linux-raid-
> } owner@vger.kernel.org] On Behalf Of Ruslan Sivak
> } Sent: Friday, May 04, 2007 12:22 PM
> } To: linux-raid@vger.kernel.org
> } Subject: raid10 on centos 5
> } 
> } I am trying to set up raid 10 and so far with no luck.  I have 4 drives,
> } and Anaconda will not let me do raid 10.  mdadm doesn't have the raid 10
> } personality loaded.  When I create the array manually like so:
> } 
> } 2 drives in /dev/md11 as raid1
> } 2 drives in /dev/md12 as raid1
> } md11 and md12 in /dev/md10 as raid0
> } 
> } Everything looks fine from the shell, but anaconda only sees md11 and
> } md12.
> } 
> } The only choice I see is to set up LVM over md11 and md12.  Is this
> } really raid10?
> } 
> } Russ
>
> You are making a RAID1+RAID0 array.
> Try making a real RAID10 array with 4 drives.  This way you would only have
> 1 array with 4 drives.
>
> >From the mdadm man page:
> Currently, Linux supports LINEAR md devices,  RAID0  (striping),  RAID1
>        (mirroring), RAID4, RAID5, RAID6, RAID10, MULTIPATH, and FAULTY.
>
> Notice RAID10 is listed, use that.  Man mdadm for more info.
>
> However, I would (and do) use RAID6.  With RAID6 any 2 disks can fail
> without data loss.  With RAID1+RAID0, any one disk can fail, a second
> failure has a 1 in 3 chance of vast data loss.
>
> I hope this helps,
> Guy
>
> -
>   


Guy,

That's what I've been trying to do.  Unfortunatelly, my distro, CentOS 5 
(based on RHEL 5, I believe), does not have the RAID10 personality in 
the kernel.  I guess I would have to compile my own kernel and load the 
module through a driver disk.  Would that work?  Are there some 
instructions somewhere I can follow?

Russ