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=-6.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 F0BC8C433E6 for ; Sat, 29 Aug 2020 15:34:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7EE820791 for ; Sat, 29 Aug 2020 15:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbgH2Pe7 (ORCPT ); Sat, 29 Aug 2020 11:34:59 -0400 Received: from smtp.hosts.co.uk ([85.233.160.19]:11923 "EHLO smtp.hosts.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728196AbgH2Pe6 (ORCPT ); Sat, 29 Aug 2020 11:34:58 -0400 Received: from host86-136-163-47.range86-136.btcentralplus.com ([86.136.163.47] helo=[192.168.1.65]) by smtp.hosts.co.uk with esmtpa (Exim) (envelope-from ) id 1kC2sa-000B64-Ea; Sat, 29 Aug 2020 16:34:56 +0100 Subject: Re: Best way to add caching to a new raid setup. To: Ram Ramesh , Roman Mamedov , "R. Ramesh" Cc: Linux Raid References: <16cee7f2-38d9-13c8-4342-4562be68930b.ref@verizon.net> <16cee7f2-38d9-13c8-4342-4562be68930b@verizon.net> <20200828224616.58a1ad6c@natsu> <448afb39-d277-445f-cc42-2dfc5210da7b@gmail.com> From: antlists Message-ID: <6a9fc5ae-1cae-a3d6-6dc3-d1a93dc1e38e@youngman.org.uk> Date: Sat, 29 Aug 2020 16:34:56 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <448afb39-d277-445f-cc42-2dfc5210da7b@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-raid-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On 28/08/2020 21:39, Ram Ramesh wrote: > One thing about LVM that I am not clear. Given the choice between > creating /mirror LV /on a VG over simple PVs and /simple LV/ over raid1 > PVs, which is preferred method? Why? Simplicity says have ONE raid, with ONE PV on top of it. The other way round is you need TWO SEPARATE (at least) PV/VG/LVs, which you then stick a raid on top. Basically, it's just KISS. Cheers, Wol