[CentOS] RAID-10 vs Nested (RAID-0 on 2x RAID-1s)

[Tim Nelson]

----- Original Message -----
> On Thu, 2012-03-29 at 16:49 -0500, Tim Nelson wrote:
> 
> > [root at c6r10tester ~]# mdadm --detail /dev/md1
> > /dev/md1:
> >         Version : 1.1
> >   Creation Time : Thu Mar 29 16:14:17 2012
> >      Raid Level : raid10
> ...
> >          Layout : near=2
> >      Chunk Size : 512K
> ...
> 
> > Am I overthinking this? Does the kernel handle the mirror/stripe
> > configuration under the hood, simply presenting me with a magical
> > RAID10 array? Or, is this something different and I really should be
> > performing the RAID creation manually as noted in option #1?
> 
> Two resources to look at are:
> 
> 1) Wikipedia "Linux MD RAID 10"
> 
> http://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10
> 
> 2) mdadm manpage section for --layout= (the raid10 part)
> 
> "Finally, the layout options for RAID10 are one of ’n’, ’o’ or ’f’..."
> 
> The key to understanding your setup is mdadm --detail "Layout:
> near=2".
> The cited Wikipedia reference for a "standard near layout" describes
> your situation.
> 

This is exactly the info I needed. Thank you for pointing me to it!

--tim