From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: some general questions on RAID Date: Sun, 07 Jul 2013 11:51:03 -0500 Message-ID: <51D99C77.4000104@hardwarefreak.com> References: <1372962602.8716.56.camel@heisenberg.scientia.net> <51D5F22C.70007@turmel.org> <1373074400.10569.49.camel@fermat.scientia.net> <51D7DADA.50200@hardwarefreak.com> <1373123715.5217.27.camel@fermat.scientia.net> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1373123715.5217.27.camel@fermat.scientia.net> Sender: linux-raid-owner@vger.kernel.org To: Christoph Anton Mitterer Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 7/6/2013 10:15 AM, Christoph Anton Mitterer wrote: > On Sat, 2013-07-06 at 03:52 -0500, Stan Hoeppner wrote: >>> Since even though you'd have one dmcrypt thread per disk now,... each of >>> them would have to en/decrypt the "same" actual data for different >>> devices... so while you have 4x threads... you need to do 4x >>> en/decryption works. >> >> This would only be true if using n-way mirroring. > Ah yes... > (as you already assumed) I missed the point with striping... ;) ... > > But also for RAID5/6 you shouldn't get n times the performance (when n > is the number of disks), probably "only" about (n-1) times respectively > (n-2) times, right? One has nothing to do with the other. We're discussing dmcrypt performance here. -- Stan