From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Raid1 replaced with raid10? Date: Mon, 07 May 2007 17:22:34 -0400 Message-ID: <463F989A.8090109@tmr.com> References: <45FF1BDF.6060304@rabbit.us> <463B2D15.7020305@rabbit.us> <463B4C4F.9030504@tmr.com> <17982.42974.461499.127486@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17982.42974.461499.127486@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Peter Rabbitson , linux-raid@vger.kernel.org List-Id: linux-raid.ids Neil Brown wrote: > On Friday May 4, davidsen@tmr.com wrote: > >> Peter Rabbitson wrote: >> >>> Hi, >>> >>> I asked this question back in march but received no answers, so here it >>> goes again. Is it safe to replace raid1 with raid10 where the amount of >>> disks is equal to the amount of far/near/offset copies? I understand it >>> has the downside of not being a bit-by-bit mirror of a plain filesystem. >>> Are there any other caveats? >>> >>> >> Clearly you have reduced capacity, since there's a mirror AND a CRC, >> otherwise I don't see any drawbacks. The performance should be much better. >> > > CRC ??? md/raid10 doesn't have any CRC. > What CRC are you thinking of? > There is an entire paragraph missing here, no doubt a finger check due to trying to post and get out to lunch. I was rambling on about raid6, mirroring 1+5, and other things which never made it. The post can be scrubbed, I was just rambling on at length about various other solutions possible. Not worth a repost, since I was way over answering his question... > To answer the original question, I assume you mean "replace" as in > "backup, create new array, then restore". > You will get different performance characteristics. Whether they > better suit your needs or not will depend largely on your needs. > > NeilBrown > > -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979