From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Waterman Subject: Re: md faster than h/w? Date: Sat, 14 Jan 2006 19:48:33 +0800 Message-ID: <43C8E511.7090207@fastmail.co.uk> References: <20060113144640.GA10566@lug.udel.edu> <43C851AD.80006@fastmail.co.uk> <20060114020523.GB24976@lug.udel.edu> <43C8B5A5.5010500@fastmail.co.uk> <43C8D5A1.5070004@tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <43C8D5A1.5070004@tls.msk.ru> Sender: linux-raid-owner@vger.kernel.org To: Michael Tokarev Cc: Ross Vandegrift , linux-raid@vger.kernel.org List-Id: linux-raid.ids Michael Tokarev wrote: > Max Waterman wrote: > [] >> My preference will probably be raid10 - ie raid0 2 drives, raid0 >> another 2 drives, and then raid1 both raid0s. My 5th disk can be a hot >> spare. Round reasonable? > > Nononono. Never do that. Instead, create two raid1s and raid0 > both, ie, just the opposite. Think about the two variants, and > I hope you'll come to the reason why raid0(2x raid1) is more > reliable than raid1(2x raid0). ;) Ah, yes. Right. I was aware of the 'difference', just had it backwards in my mind...oops. > >> Alternatively, we could probably get a 6th disk and do raid1 on >> disk #5 & #6 and install the OS on that - keeping the application >> data separate. This would be ideal, I think. For some reason, I like >> to keep os separate from application data. > > BTW, there's a raid10 module in current 2.6 kernels, which works > somewhat differently compared with raid0(2x raid1) etc. oh? and how does that compare to the MD. Although I can create md devices using mdadm, I guess I'm not completely sure what actually does the work. Max.