Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751762AbWIFRVy (ORCPT ); Wed, 6 Sep 2006 13:21:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751763AbWIFRVy (ORCPT ); Wed, 6 Sep 2006 13:21:54 -0400 Received: from smtpout.mac.com ([17.250.248.186]:767 "EHLO smtpout.mac.com") by vger.kernel.org with ESMTP id S1751762AbWIFRVx (ORCPT ); Wed, 6 Sep 2006 13:21:53 -0400 In-Reply-To: <44FE0BDE.40309@tmr.com> References: <44FB5AAD.7020307@perkel.com> <44FBD08A.1080600@tls.msk.ru> <44FE0BDE.40309@tmr.com> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Cc: Michael Tokarev , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: Raid 0 Swap? Date: Wed, 6 Sep 2006 13:21:33 -0400 To: Bill Davidsen X-Mailer: Apple Mail (2.752.2) X-Brightmail-Tracker: AAAAAQAAA+k= X-Language-Identified: TRUE Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 27 On Sep 05, 2006, at 19:44:30, Bill Davidsen wrote: > Final note: if you are building a really reliable system, RAID6 on > all data, redundant power supplies (the highest point of total > failure), then you should go to RAID0 for swap, on multiple > controllers, preferably one drives in different enclosures. RAID6 > for swap sucks rocks off the bottom of the ocean, three way RAID1 > performs well even after a one drive failure. There's also some interesting high-performance FPGA-based products out there which stack another layer or two of reed-solomon coding on top of a group of N existing drives so that you can handle up to M drive failures where M < N, and optionally also a failure of a stripe of up to K sectors out of every group of J sectors. IIRC your average CD and DVD uses this kind of encoding, so if you have a bunch of scattered errors or a single big error up to like 9k long you can still recover all the data while decoding. Those kind of matrix transformations would be dog-slow on a general purpose CPU, but with custom FPGA or VLSI chips you can do it in parallel easily better than disk bandwidth Cheers, Kyle Moffett - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/