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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35659C433EF for ; Mon, 13 Jun 2022 19:45:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233460AbiFMTpR (ORCPT ); Mon, 13 Jun 2022 15:45:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240152AbiFMTnD (ORCPT ); Mon, 13 Jun 2022 15:43:03 -0400 Received: from mail1.merlins.org (magic.merlins.org [209.81.13.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61B6A7893E for ; Mon, 13 Jun 2022 11:13:27 -0700 (PDT) Received: from rrcs-173-197-119-179.west.biz.rr.com ([173.197.119.179]:6922 helo=sauron.svh.merlins.org) by mail1.merlins.org with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94.2 #2) id 1o0nqd-0005wp-Ep by authid with srv_auth_plain; Mon, 13 Jun 2022 11:13:22 -0700 Received: from merlin by sauron.svh.merlins.org with local (Exim 4.92) (envelope-from ) id 1o0oZ0-00CEtP-5a; Mon, 13 Jun 2022 11:13:22 -0700 Date: Mon, 13 Jun 2022 11:13:22 -0700 From: Marc MERLIN To: Roman Mamedov Cc: Andrea Gelmini , Andrei Borzenkov , Zygo Blaxell , Josef Bacik , Chris Murphy , Qu Wenruo , "linux-btrfs@vger.kernel.org" Subject: Re: Suggestions for building new 44TB Raid5 array Message-ID: <20220613181322.GP1664812@merlins.org> References: <20220611145259.GF1664812@merlins.org> <20220613022107.6eafbc1c@nvm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220613022107.6eafbc1c@nvm> X-Sysadmin: BOFH X-URL: http://marc.merlins.org/ X-SA-Exim-Connect-IP: 173.197.119.179 X-SA-Exim-Mail-From: marc@merlins.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Jun 13, 2022 at 02:21:07AM +0500, Roman Mamedov wrote: > I'd suggest to put the LUKS volume onto an LV still (in case you don't), so you > can add and remove cache just to see how it works; unlike with bcache, an LVM In case I decide to give that a shot, what would the actual LVM command(s) look like to create a null LVM? You'd just make a single PV using the cryptestup decrypted version of the mdadm raid5 and then an LV that takes all of it, but after the fact you can modify the LV and add a cache? Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Home page: http://marc.merlins.org/ | PGP 7F55D5F27AAF9D08