From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: What's the typical RAID10 setup? Date: Fri, 04 Feb 2011 15:17:51 +0100 Message-ID: References: <20110131203725.GB2283@www2.open-std.org> <4D475AB5.10600@hardwarefreak.com> <20110203110428.GA26762@www2.open-std.org> <4D4B3DAE.3070502@hardwarefreak.com> <20110204070613.GA3788@www2.open-std.org> <4D4BB87A.30800@hardwarefreak.com> <20110204135343.GC4808@www2.open-std.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20110204135343.GC4808@www2.open-std.org> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 04/02/2011 14:53, Keld J=F8rn Simonsen wrote: > On Fri, Feb 04, 2011 at 12:34:00PM +0100, David Brown wrote: >> On 04/02/2011 09:27, Stan Hoeppner wrote: >>> Keld J=F8rn Simonsen put forth on 2/4/2011 1:06 AM: >>> >>>> Well RAID1+0 is not the best combination available. I would argue = that >>>> raid10,f2 is significantly better in a number of areas. >>> >>> I'd guess Linux software RAID would be lucky to have 1% of RAID dep= loyments >>> worldwide--very lucky. The other 99%+ are HBA RAID or SAN/NAS >>> "appliances" most >>> often using custom embedded RTOS with the RAID code written in asse= mbler, >>> especially in the case of the HBAs. For everything not Linux mdrai= d, RAID >>> 10 >>> (aka 1+0) is king of the hill, and has been for 15 years+ >>> >> >> I wonder what sort of market penetration small cheap SAN/NAS >> "appliances" have these days, aimed at the home markets and small >> offices. These are almost invariably Linux md raid devices, althoug= h >> the user views them as an black-box appliance. >> >> However, though they use md raid, they typically don't support RAID1= 0, >> RAID1+0, RAID10,f2, or anything other than RAID0, RAID1 and RAID5. > > I wonder why this is so. (I cannot dispute what you are saying, as I = have > not got any experience with any small SAN/NAS devices). > > Anyway, Linux NAS/SAN devices should run a kernel that should be able= to > run MD raid10 and RAID 1+0 - as this has been in the Linux kernel > for more than 5 years. > I think it is just a matter of simplifying the interface for the=20 expected use of the target audience. The typical customer of such NAS=20 appliances doesn't know enough about raid to understand the detailed=20 pros and cons of different types, and is unlikely to care about small=20 performance differences. Thus they have the options of raid0 and JBD=20 for maximal space per $, raid1 for two disks with redundancy, and raid5= =20 for more disks with redundancy. They don't have hot spares, raid6,=20 mixing raid levels on different partitions, etc. Keep it simple, and=20 people can use it. Of course, you can always access these devices directly, or with ssh,=20 and re-arrange things as you want. It's only the web-based user=20 interface that is limited. > For c0mpanies that sell Linux NAS/SAN devices, I would have thought t= hat > they would have at least one engineer following this list. > Maybe they will not disclose themselves, but are there some of you ou= t > here? > > And what kind of support of RAID types are available on your box? > > And maybe the more advanced stuff is available, but only in some CLI. > The configuration web server could be without the more advanced oprio= ns. > But then: why not use options that kind of doubles the performance > compared to competitors? > > Are the raid 1+0 and md raid10 options available via some ssh > or other CLI access mechanisms? I know on routers, there are > normally a CLI interface. > > Furthermore, Linux has a good penetration in the server market. > And I think most people would run servers with raids, if they do > something serious. So Linux RAID should be more than 1 %, at least > in the server market. > -- 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