From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pieter De Wit Subject: Re: Using Video cards (CUDA) for RAID parity Date: Fri, 13 Dec 2013 05:57:29 +1300 Message-ID: <52A9EAF9.6020804@insync.za.net> References: <52A98FAF.4000205@insync.za.net> <52A9A380.50805@hesbynett.no> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52A9A380.50805@hesbynett.no> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 13/12/2013 00:52, David Brown wrote: > On 12/12/13 11:27, Pieter De Wit wrote: >> Hi List, >> >> Given the recent work done with techs like CUDA etc. - has the idea been >> floated to use the video card for RAID parity calculations vs the CPU ? >> Bitcoin and plenty others have shown the true speed of these cards. This >> might be a cheaper version of a RAID card. >> >> Cheers, >> >> Pieter > I am almost certain that you /could/ use a graphics card to do parity > calculations faster than a cpu core. However, even the newly proposed > multi-parity calculations are not a big challenge for a modern cpu. A > bigger issue is getting optimal threading so that multiple cores (or at > least threads) can be used at the same time, and this work is well under > way already. Once that work is completed, my guess is that I/O, cache > or memory bandwidth will be the bottleneck for big raid arrays rather > than cpu power - and using graphics cards will not help there. > > David > > > -- > 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 http://vger.kernel.org/majordomo-info.html Ah - I see - I also thought it was multi-threaded, but, tbh, I never looked that hard into it. My question comes from the fact that I now have access to 32x750gig (and more if needed) drives on a fiber array. The down side is that I only have *old* CPUs driving the array. RAID5's sync speed (15 disks) is 8meg/second. Change the array to RAID10 and the sync speed is above 100meg/second. I, naively perhaps, assumed the bottleneck to be the Intel CPU's which sparked this idea. What about block level hashing ? (Unless this is already done and I just never knew it :) ) Cheers, Pieter