From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: md RAID with enterprise-class SATA or SAS drives Date: Fri, 11 May 2012 09:10:32 +0200 Message-ID: <4FACBB68.2080304@hesbynett.no> References: <4FAAE8F1.8000600@pocock.com.au> <4FABC7C6.4030107@turmel.org> <4FAC2FF2.5060305@hardwarefreak.com> <4FAC40BC.1060300@hesbynett.no> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Roberto Spadim Cc: stan@hardwarefreak.com, Phil Turmel , Marcus Sorensen , Daniel Pocock , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 11/05/2012 00:49, Roberto Spadim wrote: > i have dell servers and i use raid1 in every servers just raid10 or > raid0 are in hardware because hotswap with hardware is easier to > implement, but if mdraid could do the job, i don=B4t see why use hard= ware > raid devices (just if they have batery) > I think for simple situations, such as just wanting a straight mirror o= f=20 two disks, then hardware raid provided by the supplier is often a good=20 choice. As you say, it can make hotswap easier - you get things like=20 little red and green lights on the disk drives. And the vendor support= s=20 it and knows how it works. Also if you've got a more serious hardware=20 with BBWC or similar features, then these features may be the deciding=20 points. But there is no doubt that md raid is a lot more flexible than any othe= r=20 raid system, it is often faster (especially for smaller setups -=20 raid10,far being a prime example), and the money you save on raid cards= =20 can be spent on extra disks, UPS, etc. One thing that may be an advantage either way is ease of configuration,= =20 monitoring, maintenance, and transfer of disks between systems. With m= d=20 raid, you have a consistent system that is independent of the hardware=20 and setup, while every hardware raid system has its own proprietary=20 tools, setup, hardware, monitoring software, etc. So this is often a=20 win for md raid - but if you support several hardware raid arrays, and=20 use the same vendor for them all, then you have a consistent system=20 there too. > 2012/5/10 David Brown > > > On 10/05/12 23:15, Stan Hoeppner wrote: > > On 5/10/2012 8:51 AM, Phil Turmel wrote: > > Hardware RAID cards usually offer battery-backed write > cache, which is > very valuable in some applications. I don't have a need = for > that kind > of performance, so I can't speak to the details. (Is Sta= n H. > listening?) > > > Yes, I'm here to drop the hammer, and start a flame war. ;) > I've been > lurking and trying to stay out of the fray, but you "keep > dragging me > back in!" --Michael Corleone > > I find the mere existence of this thread a bit comical, as wi= th all > others that have preceded it. I made the comment on this lis= t quite > some time ago that md raid is mostly used by hobbyists, and t= ook > a lot > of heat for that. The existence of this thread adds ammuniti= on > to that > argument. > > > I think you've got that a bit backwards. Most hobbyists (or > low-budget users) who use raid other than motherboard fakeraid wi= ll > choose Linux md raid. It may well be that most users of md raid > /are/ hobby or low-budget users. But your implication - that > professionals don't use md raid - is completely wrong. > > It's more likely that it is hobby users that discuss these sorts = of > things - professionals just pay the money that the server > manufacturer asks for its supported disks, since paying that is > cheaper than spending time discussing things. I know I mostly > follow lists like this in my free time (as a hobbiest) rather tha= n > in work time (as a professional). > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-r= aid" in > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/__majordomo-info.ht= ml > > > > > > -- > 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