bin/166589: atacontrol(8) incorrectly treats RAID10 and 0+1 the same

[Alexander Motin]

The following reply was made to PR bin/166589; it has been noted by GNATS.

From: Alexander Motin <mav at FreeBSD.org>
To: Allen Landsidel <landsidel.allen at gmail.com>
Cc: bug-followup at FreeBSD.org
Subject: Re: bin/166589: atacontrol(8) incorrectly treats RAID10 and 0+1 the
 same
Date: Tue, 15 Jan 2013 18:25:14 +0200

 At what point have we talked about hardware RAID controllers? ataraid(8)
 never controller hardware RAID controllers, but only Soft-/Fake-RAIDs
 implemented by board BIOS'es during boot and OS drivers after that.
 
 On 15.01.2013 18:22, Allen Landsidel wrote:
 > Your solution then is to require everyone use software raid on their
 > hardware raid controllers?
 > 
 > On 1/15/2013 11:20, Alexander Motin wrote:
 >> On 15.01.2013 18:03, Allen Landsidel wrote:
 >>> I'm also extremely interested to hear how you intend to "handle it as
 >>> RAID10 at the OS level" since that is, in fact, impossible.
 >> Easily!
 >>
 >>> If it's a RAID0+1 in the controller, than it's a RAID0+1. Period.  The
 >>> OS can't do anything about it.  A single disk failure is still knocking
 >>> half the array offline (the entire failed RAID-0) and you are left with
 >>> a functioning RAID-0 with no redundancy at all.
 >> ataraid(8) in question (and its new alternative graid(8)) controls
 >> software RAIDs. It means that I can do anything I want in software as
 >> long as it fits into existing on-disk metadata format. If RAID BIOS
 >> wants to believe that two failed disks of four always mean failed array
 >> -- it is their decision I can't change. But after OS booted nothing will
 >> prevent me from accessing still available data replicas.
 >>
 >>> On
 > 
 
 
 -- 
 Alexander Motin