Date: Tue, 15 Jan 2013 08:20:01 GMT From: Alexander Motin <mav@FreeBSD.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/166589: atacontrol(8) incorrectly treats RAID10 and 0+1 the same Message-ID: <201301150820.r0F8K1aD027442@freefall.freebsd.org>
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The following reply was made to PR bin/166589; it has been noted by GNATS. From: Alexander Motin <mav@FreeBSD.org> To: Allen Landsidel <landsidel.allen@gmail.com> Cc: bug-followup@FreeBSD.org Subject: Re: bin/166589: atacontrol(8) incorrectly treats RAID10 and 0+1 the same Date: Tue, 15 Jan 2013 10:12:14 +0200 That is clear and I had guess you mean it, but why do you insist that such RAID0+1 variant should even exist if it has no benefits over RAID10, and why it should be explicitly available to user? On 15.01.2013 04:51, Allen Landsidel wrote: > They are not variants in terminology, they are different raid levels. > Raid0+1 is two RAID-0 arrays, mirrored into a RAID-1. if one of the > disks fails, that entire RAID-0 is offline and must be rebuilt, and all > redundancy is lost. A RAID-10 is composed of N raid-1 disks combined > into a RAID-0. If one disk fails, only that particular RAID-1 is > degraded, and the redundancy of the others is maintained. > > 0+1 cannot survive two failed disks no matter how many are in the > array. 10 can survive half the disks failing, if it's the right half. > > This is something people who've never used more than 4 disks fail to > grasp, but those of us with 6 (or many many more) know very well. > > On 1/14/2013 21:46, Alexander Motin wrote: >> There could be variants in terminology, but in fact for most of users >> they are the same. If you have opinion why they should be treated >> differently, please explain it. -- Alexander Motin
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