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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 225DAC433E1 for ; Thu, 27 Aug 2020 12:57:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0886F22BF5 for ; Thu, 27 Aug 2020 12:57:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729102AbgH0MnZ (ORCPT ); Thu, 27 Aug 2020 08:43:25 -0400 Received: from dcvr.yhbt.net ([64.71.152.64]:43024 "EHLO dcvr.yhbt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729085AbgH0MmM (ORCPT ); Thu, 27 Aug 2020 08:42:12 -0400 Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 35DDF1F66E; Thu, 27 Aug 2020 12:41:47 +0000 (UTC) Date: Thu, 27 Aug 2020 12:41:47 +0000 From: Eric Wong To: linux-btrfs@vger.kernel.org Subject: adding new devices to degraded raid1 Message-ID: <20200827124147.GA16923@dcvr> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org I don't need to do it right away, but is it possible to add new devices to a degraded raid1? One thing I might do in the future is replace a broken big drive with two small drives. It may even be used to migrate to SSDs. Since btrfs-replace only seems to do 1:1 replacements, and I needed to physically remove an existing broken device to make room for the replacements, could I do something like: mount -o degraded /mnt/foo btrfs device add small1 small2 /mnt/foo btrfs device remove broken /mnt/foo ? Anyways, so far raid1 has been working great for me, but I have some devices nearing 70K Power_On_Hours according to SMART Thanks.