The following reply was made to PR bin/166589; it has been noted by GNATS. From: Allen Landsidel <landsidel.al...@gmail.com> To: Alexander Motin <m...@freebsd.org> Cc: bug-follo...@freebsd.org Subject: Re: bin/166589: atacontrol(8) incorrectly treats RAID10 and 0+1 the same Date: Tue, 15 Jan 2013 10:28:53 -0500
Most devices typically only support one level or the other, but not both. I don't "Insist that it should exist", it *does* exist. Both levels do, and they are not the same thing. As for why it should be "available" to the user, I think that's a pretty silly question. If their hardware supports one or both levels, they should be available to the user -- and called by their correct names. On 1/15/2013 03:12, Alexander Motin wrote: > 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. _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
