RAID 0+1

[Dave Mitchell]

On Tue, Mar 21, 2006 at 08:00:24AM -0600, Jeff Vian wrote:
> Why not raid 5?  The available space is n-1 for the number of drives
> used.  A single drive failure does not impact function at all because of
> the redundancy and parity stripe that keeps all data intact.

But with RAID 5, performance is very bad after a single drive failure.
> 
> Raid 0+1 gives at best n/2 space and means you only have 3*73 or a total
> of 219gb available.  A single disk problem takes out the entire mirror
> copy (3 disks) because of striping.  A data error on one copy and any
> other error (even in a different location) on the second copy will take
> everything out (again because of the striping effect of raid 0). 

Huh? Two drive failures will lose all your data on RAID5. Two drive
failures on RAID 0+1 may or may not lose all your data depending on
circumstances.

> If I have the option I would personally never recommend a raid 10
> configuration.

I would always recommend 1+0 over 5 if I can afford it.

-- 
The crew of the Enterprise encounter an alien life form which is
suprisingly neither humanoid nor made from pure energy.
    -- Things That Never Happen in "Star Trek" #22