From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roberto Spadim Subject: Re: wish for Linux MD mirrored raid types Date: Mon, 9 May 2011 17:12:09 -0300 Message-ID: References: <20110506071752.GA22063@www2.open-std.org> <20110509195953.GB26847@www2.open-std.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20110509195953.GB26847@www2.open-std.org> Sender: linux-raid-owner@vger.kernel.org To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= Cc: Emmanuel Noobadmin , linux-raid@vger.kernel.org List-Id: linux-raid.ids hum, if you check docs, source, and test, you will check that md raid can have >=3D2 mirrors without problems, you can have 3 disks and 3 mirrors, you can have 3 disks and 2 mirrors, you can have 1 disk with 10 partitions, and each partition be a mirror of each other, the point here is, md software isn=B4t a hardware raid, it=B4s very near but have more features, i don=B4t know if we should change md to allow it be compatible with a 'industrial standard' since we have more feature than standard, you must check what you want and use it maybe some article at wiki, standard X, layout Y, level W =3D md raid level A layout B devices C mirrors D spares E ..... i think this is welcome to linux wiki page 2011/5/9 Keld J=F8rn Simonsen : > On Mon, May 09, 2011 at 01:22:42PM +0800, Emmanuel Noobadmin wrote: >> On 5/6/11, Keld J=F8rn Simonsen wrote: >> > Hi List >> > >> > based on the recent discussion, that showed lacking knowledge >> > on Linux MD RAID10 features, I have some thoughts: >> > >> > It is really hard to disseminate information on "new" features >> > in MD RAID. RAID10 has been in the kernel since 2.6.9 - from 2004. >> > I have tried to give info on RAID10 at a number of web pages, >> > and still many people, even on our linux-raid list are not aware >> > of it. >> > >> > Also many people are confused about Linux MD raid10 and RAID1+0. >> > >> > So I think we shopuld rather name things in another way. >> > >> > I would like linux MD raid10 functionality to be part of the Linux= MD >> > RAID1 module, and be called raid1. This is in accordance with the >> > use of the RAID1 term as standadized by SNIA. In fact the RAID10-o= ffset >> > layout is an implementation of a SNIA RAID specification. The RAID= 10-near >> > layout is an implementation of a simple RAID layout. And the RAID1= 0-far >> > layout is just another layout far a mirrored RAID. =A0So all these= types >> > could just be defined as different RAID1 layouts. >> >> Giving my noob's 2 cents worth although I haven't followed the >> original discussion. As a noob, =A0I think doing this will just conf= use >> us more. >> >> There are plenty of existing materials around for those of us who tr= y >> to figure things out by googling. As it is, our (or maybe just me) >> understanding is Linux RAID 1 is just like every other raid 1: simpl= e >> and straightforward, 2 drives mirroring each other. >> >> This is is also usually the level that most of us start with. If the >> instructions are short, easy to understand and simple to implement, = we >> usually gain confidence in using it and exploring mdraid further. >> >> Most of us noobs are also aware that RAID 10 is more complicated and >> there are two versions, i.e. 1+0 and 0+1. So psychologically, I had = no >> problems accepting that once I looked into it, there were much more >> complex stuff and all these possible layouts: mdraid is cool! >> >> Now, if RAID 10 was renamed to RAID 1, with the corresponding change >> in documentation, what's going to happen for us noobs is this: "Omg, >> why are there so many different versions and options just for raid 1= ?" >> and importantly "Why is this manual/wiki different from the tons of >> other pages about using mdraid 1?" For some, this would mean mdraid = is >> too difficult even for raid 1, mdraid is not cool! :) >> >> So newbies will get more confused/frustrated as a result. >> >> Personally, I had to spend some time figuring out (I'm noob and I'm >> not very smart) the different layouts from the examples on wiki. Thi= s >> is because there wasn't enough examples, at least to me, to clearly >> show what's the difference if more/less disks were used. So for me, >> and other noobs, it would probably help if the wiki had more example= s >> of each layout, maybe graphics to show the difference since it's >> probably easier to see things if they were colour coded blocks rathe= r >> than stuff like A1 a1 A2 a2. >> >> This and perhaps more elaboration on the difference between mdraid 1= 0 >> and normal raid 10 =A0would probably be better to clear up confusion >> than renaming something we might have some familiarity with, into >> something we also already have familiarity, resulting in something >> that contradicts existing familiarity. > > I see your point. Given Neil's input I think we should =A0rateher cal= l it > raid1e. > > Best regards > keld > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =A0http://vger.kernel.org/majordomo-info.html > --=20 Roberto Spadim Spadim Technology / SPAEmpresarial -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html