From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37ACDC433B4 for ; Wed, 12 May 2021 18:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7FA2613C4 for ; Wed, 12 May 2021 18:55:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343564AbhELSrz (ORCPT ); Wed, 12 May 2021 14:47:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347553AbhELR2t (ORCPT ); Wed, 12 May 2021 13:28:49 -0400 X-Greylist: delayed 279 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 12 May 2021 10:27:23 PDT Received: from u17383850.onlinehome-server.com (u17383850.onlinehome-server.com [IPv6:2607:f1c0:83f:ac00::a6:f62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1631AC061347 for ; Wed, 12 May 2021 10:27:22 -0700 (PDT) Received: by u17383850.onlinehome-server.com (Postfix, from userid 5001) id 80E28770; Wed, 12 May 2021 13:27:20 -0400 (EDT) Date: Wed, 12 May 2021 13:27:20 -0400 From: David T-G To: list Linux RAID Subject: Re: raid10 redundancy Message-ID: <20210512172720.GY1415@justpickone.org> References: <60950C7B.5040706@youngman.org.uk> <8333ded7-8805-18df-13d8-166ba021ac02@turmel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8333ded7-8805-18df-13d8-166ba021ac02@turmel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Phil, et al -- ...and then Phil Turmel said... % % I do this for my medium-speed read-mostly tasks. Raid10,n3 across 4 % or 5 disks gives me redundancy comparable to raid6 (lose any two) % without the CPU load of parity and syndrome calculations. I've been reading and I still need to catch up on the notation, but how much space do you get in the end? I'm hoping to grow our disk farm and end up with 8+ disks. I'm more than a bit nervous about RAID5 across a bunch of 6T (or bigger) disks, so I've been thinking of RAID6. That would give me 6x6 = 36T plus two parity. Putting 8 disks in RAID10 should give me 6x4 = 24T with mirroring. That's a pretty hefty space penalty :-( But ... How does RAID10 across 5 disks as above 1) work and 2) work out? If you had 8 disks with a huge need for space, how would y'all lay out everything? % % Phil Thanks in advance :-) :-D -- David T-G See http://justpickone.org/davidtg/email/ See http://justpickone.org/davidtg/tofu.txt