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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1291C433F5 for ; Thu, 28 Oct 2021 13:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A7F761038 for ; Thu, 28 Oct 2021 13:49:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230480AbhJ1NwD (ORCPT ); Thu, 28 Oct 2021 09:52:03 -0400 Received: from www18.qth.com ([69.16.238.59]:42650 "EHLO www18.qth.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231137AbhJ1Nvu (ORCPT ); Thu, 28 Oct 2021 09:51:50 -0400 X-Greylist: delayed 831 seconds by postgrey-1.27 at vger.kernel.org; Thu, 28 Oct 2021 09:51:50 EDT Received: from [73.207.192.158] (port=44936 helo=justpickone.org) by www18.qth.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mg5Z7-0005x8-T3 for linux-raid@vger.kernel.org; Thu, 28 Oct 2021 08:35:31 -0500 Date: Thu, 28 Oct 2021 13:36:27 +0000 From: David T-G To: Linux RAID Subject: growing a RAID5 array by adding disks later Message-ID: <20211028133626.GX6557@justpickone.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - www18.qth.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - justpickone.org X-Get-Message-Sender-Via: www18.qth.com: authenticated_id: dmail@justpickone.org X-Authenticated-Sender: www18.qth.com: dmail@justpickone.org X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Hi, all -- It's time to replace a few 4T disks in our little server. I don't particularly want to go back with more 4T disks (although the same model sure are cheap these days! :-) and figure I should put in larger drives as I go. I am then left with weighing simple $/G vs total price; bigger drives can be cheaper per volume but of course more overall. My first approach is to put newer, larger drives in place and expect to grow into the empty space when all of the old ones have been swapped out. But ... If I were to splurge and buy 3ea big drives to replace all of the space that I have now, how practical is it to grow that RAID5 array by adding additional drives later? My eventual goal would be to get to 8-10 devices in a RAID6 layout (two "extras"), but of course I can't afford that today. Do I have an easy path to get there in the long run? [BTW, can I convert an array from RAID5 to RAID6, too?] On the other hand, I do have the empty slots (currently filled with scratch drives here and there), so I could both replace my aging drives and add more and just grow this array 1) if the growth idea is practical and 2) if I don't get to splurge. TIA :-D -- David T-G See http://justpickone.org/davidtg/email/ See http://justpickone.org/davidtg/tofu.txt