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 2F8F9C43334 for ; Sat, 11 Jun 2022 14:53:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236418AbiFKOxO (ORCPT ); Sat, 11 Jun 2022 10:53:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233529AbiFKOxM (ORCPT ); Sat, 11 Jun 2022 10:53:12 -0400 Received: from mail1.merlins.org (magic.merlins.org [209.81.13.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9176DF0F for ; Sat, 11 Jun 2022 07:53:08 -0700 (PDT) Received: from [172.58.35.216] (port=61451 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 1o01le-0003VR-00 by authid with srv_auth_plain; Sat, 11 Jun 2022 07:53:01 -0700 Received: from merlin by sauron.svh.merlins.org with local (Exim 4.92) (envelope-from ) id 1o02Tz-008xWk-1c; Sat, 11 Jun 2022 07:52:59 -0700 Date: Sat, 11 Jun 2022 07:52:59 -0700 From: Marc MERLIN To: Andrea Gelmini , Roman Mamedov Cc: 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: <20220611145259.GF1664812@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220611143033.56ffa6af@nvm> <20220611143033.56ffa6af@nvm> X-Sysadmin: BOFH X-URL: http://marc.merlins.org/ X-SA-Exim-Connect-IP: 172.58.35.216 X-SA-Exim-Mail-From: marc@merlins.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Sat, Jun 11, 2022 at 09:27:57AM +0200, Andrea Gelmini wrote: > Il giorno sab 11 giu 2022 alle ore 09:16 Marc MERLIN > ha scritto: > > As for bcache, I'm really thinking about droppping it, unless I'm told > > it should be safe to use. > > https://lwn.net/Articles/895266/ Mmmh, bcachefs, I was not aware of this new one. Not sure if I want to add yet another layer, esepcially if it's new. On Sat, Jun 11, 2022 at 02:30:33PM +0500, Roman Mamedov wrote: > > 2) echo 0fb96f02-d8da-45ce-aba7-070a1a8420e3 > /sys/block/bcache64/bcache/attach > > gargamel:/dev# cat /sys/block/md7/bcache/cache_mode > > [writethrough] writeback writearound none > > Maybe try LVM Cache this time? Hard to know either way, trading one layer for another, and LVM has always seemed heavier > > 3) cryptsetup luksFormat --align-payload=2048 -s 256 -c aes-xts-plain64 /dev/bcache64 > > 4) cryptsetup luksOpen /dev/bcache64 dshelf1 > > What's the threat scenario for LUKS on the array? In case my computer gets stolen, and indeed being able to recycle old drives without having to worry, is a nice bonus. > > 5) mkfs.btrfs -m dup -L dshelf1 /dev/mapper/dshelf1 > > Personally I have switched from Btrfs on MD to individual disks and MergerFS. That gives you no redundancy if a drive disk, correct? Thanks, 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