From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Fedyk Subject: Re: New RAID-6 snapshot Date: Tue, 30 Dec 2003 10:58:35 -0800 Sender: linux-raid-owner@vger.kernel.org Message-ID: <20031230185835.GV1882@matchmail.com> References: <20031230172420.GS1882@matchmail.com> <3FF1C589.3070906@zytor.com> <20031230184336.GU1882@matchmail.com> <3FF1C91E.4090600@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3FF1C91E.4090600@zytor.com> To: "H. Peter Anvin" Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, Dec 30, 2003 at 10:51:10AM -0800, H. Peter Anvin wrote: > Now, you'd never use RMW only; it's only used when it should be faster > than RCW, which is why I'm a bit surprised about the performance > degradation. With only six drives in my test system it's pretty clear > that RMW should very rarely be invoked, however, the performance ought > to have stayed the same rather than slip. You mentioned that none of your snapshots have RMW in them. Can you put up a patch that adds RMW to the snapshots? Maybe someone will notice something... Did you get any data corruption with the RMW patch applied?